{ "schemaVersion": "1.0.0", "constitutionVersion": "1.0.0", "createdAt": "2026-08-12T00:00:00Z", "description": "Append-only Evidence Passport records. Old revisions are immutable; corrections create a new revision and preserve the previous permalink.", "entity": { "type": "project", "id": "mexico-city-hoy-no-circula", "title": "Hoy No Circula: Mexico City's Plate-Based Driving Restriction", "canonicalUrl": "https://1001smartcities.org/projects/mexico-city-hoy-no-circula/" }, "currentRevisionId": "2026-08-27-landmark-p6-uplift", "revisions": [ { "id": "2026-08-14-evidence-baseline", "createdAt": "2026-08-14T00:00:00Z", "effectiveAt": "2026-07-26", "changeType": "baseline", "summary": "Created the first structured Evidence Passport with 12 claims and 9 source dossiers.", "preparedBy": { "type": "automation", "label": "AI-assisted evidence preparation", "humanApproved": false }, "review": { "status": "unreviewed", "by": null, "date": null, "note": "Awaiting operator and domain-expert review; publication of this revision implies neither." }, "changes": [ { "operation": "add", "path": "/evidencePassport", "summary": "Added claim-level evidence mapping and source dossiers." }, { "operation": "add", "path": "/revisionHistory", "summary": "Established a permanent, hash-addressed baseline revision." } ], "snapshotHash": "sha256:0d70be14b32a6f7e0a4a758eefce3f22dc1c471137a0d22c49cbc27de41b8931", "snapshot": { "asOf": "2026-07-26", "projectFingerprint": "sha256:00e3b6effe89842d9adb11be6f6d296c6868dcb4f46cc90ff60d5a7d1139c75d", "assurance": { "status": "unreviewed", "scope": "evidence-passport-revision", "statement": "AI-assisted structural preparation. This revision has not been reviewed by a human or subject-matter expert.", "machineChecks": [ "schema", "publication-diff-contract", "material-project-fingerprint", "claim-text-drift", "source-reference-resolution", "complete-source-dossier", "snapshot-hash" ] }, "projectState": { "status": "live", "outcome": "ongoing", "evidenceGrade": "peer-reviewed", "timeline": { "started": 1989, "ended": null } }, "governance": { "operator": "Secretaria del Medio Ambiente de la Ciudad de Mexico (SEDEMA), with the Comision Ambiental de la Megalopolis (CAMe) coordinating the metropolitan zone and traffic police enforcing on the street", "actorTypes": [ "city-government", "regional-government" ], "fundingModel": "public", "fundingDescription": null, "cost": null, "ownership": null, "decisionRights": null, "exitConditions": null }, "claims": [ { "id": "clm-c05142d557d70a65", "field": "impact", "text": "Davis (Journal of Political Economy 116(1), 2008) found 'across pollutants and specifications there is no evidence that the restrictions have improved air quality', together with evidence that the ban raised the total number of vehicles in circulation and shifted the fleet toward high-emission cars.", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24" ], "supportNote": "Two further peer-reviewed studies cited in the entry corroborate the null result and the second-car workaround.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-6154072a52ebdd2b", "field": "body", "text": "Mexico City started keeping cars off the road one weekday a week by the last digit of their plate in November 1989, after an ozone emergency, and made the rule permanent the following year", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24", "src-afdaf4d2258b3ff4" ], "supportNote": "Davis dates the programme to November 1989 and its permanence to the following year; El Financiero carries the same origin during an ozone emergency.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-d81cf531abf232f9", "field": "body", "text": "It began on 20 November 1989 as an emergency measure named ‘Un Día sin Auto’", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-afdaf4d2258b3ff4" ], "supportNote": "El Financiero: the programme began on 20 November 1989 as an emergency measure named 'Un Dia sin Auto' during an ozone emergency.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-ee48b27635074471", "field": "body", "text": "A compulsory emissions test every six months assigns each car a hologram, and that reading decides how hard the ban bites: holograms 00 and 0 drive every day, hologram 1 also rests two Saturdays a month, hologram 2 every Saturday", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-debbf8eec8ff1891", "src-7d81a556f40673ac" ], "supportNote": "CAMe's description of the programme carries the hologram tiers and which of them rest on Saturdays; SEDEMA is the operator page for the same rules.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-b110d027832a161a", "field": "body", "text": "When the metropolitan monitoring network pushes ozone past the contingency threshold the regional environment commission declares a ‘Fase I’ that pulls even exempt cars off the road", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ad142b48dbcb7470", "src-debbf8eec8ff1891" ], "supportNote": "CAMe declares the contingency and a Fase I declaration extends the driving ban to otherwise exempt vehicles.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-aaf51da274454a23", "field": "body", "text": "CAMe activated five ozone Fase I contingencies in 2025 alone", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ad142b48dbcb7470" ], "supportNote": "The government/CAMe record of ozone contingencies gives five Fase I activations in 2025.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-0b5f70ac48d9cee9", "field": "body", "text": "‘across pollutants and specifications there is no evidence that the restrictions have improved air quality’", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24" ], "supportNote": "Verbatim from the paper's abstract.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-31c3f86ab4d2e7aa", "field": "body", "text": "evidence that the ban raised the total number of vehicles in circulation and shifted the fleet toward high-emission cars", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24" ], "supportNote": "The same paper reports the increase in total vehicles and the shift toward high-emission cars.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-26c8718fff3952dd", "field": "body", "text": "an initial drop in car use followed by a rise in the household vehicle stock within eleven months", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-1aed7de45827ff4b" ], "supportNote": "Gallego, Montero and Salas measure an initial fall in car use followed by a rise in the household vehicle stock within eleven months.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-a2d6ea97cf37a835", "field": "body", "text": "the July 2008 Saturday extension had virtually no discernible effect across eight pollutants, and no sign that drivers switched to metro, bus or light rail", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-78b678356a3b5670" ], "supportNote": "Davis 2017 tests the Saturday extension across eight pollutants and finds virtually no discernible effect and no modal shift.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-d8a858260451ab03", "field": "body", "text": "drivers shifting trips onto lightly policed roads", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-344cf108280f6545" ], "supportNote": "Guerra and Millard-Ball examine behavioural responses to the ban, including trips shifted onto lightly policed roads. Cited from the abstract; the publisher page was blocked from this desk.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-123a2c9c7699aada", "field": "body", "text": "Press reporting describes photo-enforcement cameras in Mexico City that sanction Hoy No Circula violations as well as speeding", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-6d20cebdd4a72790" ], "supportNote": "Media-grade only: adn40 reports cameras in CDMX that sanction Hoy No Circula violations as well as speeding. No operator document confirms the scale.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } } ], "sources": [ { "id": "src-ace305ebc8ebcd24", "title": "Davis, 'The Effect of Driving Restrictions on Air Quality in Mexico City', Journal of Political Economy 116(1), 2008, pp. 38-81", "url": "https://econpapers.repec.org/article/ucpjpolec/v_3a116_3ay_3a2008_3ai_3a1_3ap_3a38-81.htm", "publisher": { "name": null, "domain": "econpapers.repec.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-c05142d557d70a65", "clm-6154072a52ebdd2b", "clm-0b5f70ac48d9cee9", "clm-31c3f86ab4d2e7aa" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-14", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "The load-bearing null result, abstract verbatim: 'In 1989, the government of Mexico City introduced a program, Hoy No Circula, that bans most drivers from using their vehicles one weekday per week on the basis of the last digit of the vehicle's license plate... Across pollutants and specifications there is no evidence that the restrictions have improved air quality. Evidence from additional sources indicates that the restrictions led to an increase in the total number of vehicles in circulation as well as a change in composition toward high-emissions vehicles.' Publisher page journals.uchicago.edu/doi/10.1086/529398; the author's own copy is at faculty.haas.berkeley.edu/ldavis/Davis%20JPE%202008.pdf but did not render from this desk, so the abstract was verified against this indexed mirror.", "exact": false }, "preservation": { "archiveUrl": "https://web.archive.org/web/20240428163441/https://econpapers.repec.org/article/ucpjpolec/v_3a116_3ay_3a2008_3ai_3a1_3ap_3a38-81.htm", "archivedAt": "2024-04-28", "contentHash": null, "status": "archive-linked" } }, { "id": "src-78b678356a3b5670", "title": "Davis, 'Saturday Driving Restrictions Fail to Improve Air Quality in Mexico City', Scientific Reports 7:41652, 2017", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC5289101/", "publisher": { "name": null, "domain": "pmc.ncbi.nlm.nih.gov", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-a2d6ea97cf37a835" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-14", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Dates the Saturday extension and grades it: 'Mexico City's driving restrictions were expanded to include Saturdays on July 5th, 2008.' and 'Overall, there is little evidence that the program expansion improved air quality.' Also the sentence this entry uses on enforcement: 'City police vigorously enforce the restrictions and vehicles violating the ban are easy to spot. Drivers caught violating the rules must pay a hefty fine and their vehicles are impounded for 48 hours.'", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-1aed7de45827ff4b", "title": "Gallego, Montero and Salas, 'The effect of transport policies on car use: Evidence from Latin American cities', Journal of Public Economics 107, 2013, pp. 47-62", "url": "https://econpapers.repec.org/RePEc:eee:pubeco:v:107:y:2013:i:c:p:47-62", "publisher": { "name": null, "domain": "econpapers.repec.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-26c8718fff3952dd" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-14", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Independently dates the programme to November 1989 and measures the second-car response: an expected short-run fall in car use followed by a rapid rise in the household vehicle stock inside eleven months, with a transport cost put at about 5 per cent of the value of the vehicle stock at implementation. Cited for the rebound, not for any air-quality figure.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-7d81a556f40673ac", "title": "SEDEMA, Ciudad de Mexico — Programa Hoy No Circula", "url": "https://sedema.cdmx.gob.mx/programas/programa/hoy-no-circula", "publisher": { "name": null, "domain": "sedema.cdmx.gob.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-ee48b27635074471" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-14", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "The operator's own programme page and the correct citation for the current rules. Direct fetch returned 503 from this desk on 2026-07-26; the rules were corroborated against the CAMe description and the 2026 press cited below, which agree on hours, coverage and hologram tiers.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-debbf8eec8ff1891", "title": "Comision Ambiental de la Megalopolis — 'El Programa Hoy No Circula que aplica en la Zona Metropolitana del Valle de Mexico'", "url": "https://www.gob.mx/comisionambiental/prensa/el-programa-hoy-no-circula-que-aplica-en-la-zona-metropolitana-del-valle-de-mexico", "publisher": { "name": null, "domain": "gob.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-ee48b27635074471", "clm-b110d027832a161a" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-14", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "The metropolitan authority's own description, carrying the coverage and hours used in the snippet: 'Aplica en las 16 alcaldias de la Ciudad de Mexico y en 18 municipios conurbados del Estado de Mexico, de lunes a sabado de 5:00 a 22:00 h' ('It applies in the 16 boroughs of Mexico City and in 18 adjoining municipalities of the State of Mexico, Monday to Saturday from 5:00 to 22:00'), and the hologram rule: 'Los vehiculos con holograma 1 no circulan dos sabados del mes segun su terminacion, mientras que los vehiculos con holograma 2 no circulan ningun sabado del mes' ('Hologram 1 vehicles do not drive on two Saturdays a month according to their plate ending, while hologram 2 vehicles do not drive on any Saturday'). Direct fetch blocked (403); the carrying sentences were confirmed by search.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-ad142b48dbcb7470", "title": "Gobierno de Mexico / CAMe — Fase I de contingencia ambiental atmosferica por ozono en la ZMVM", "url": "https://www.gob.mx/comisionambiental/prensa/se-mantiene-la-fase-i-de-contingencia-ambiental-atmosferica-por-ozono-en-la-zona-metropolitana-del-valle-de-mexico-424546", "publisher": { "name": null, "domain": "gob.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-b110d027832a161a", "clm-aaf51da274454a23" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-14", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Establishes who declares a contingency and that a declaration extends the driving ban. CAMe activated five ozone Fase I contingencies in 2025 alone (26 February, 18 March, 1, 23 and 25 April). The activation threshold is reported by Mexican press as 150 IMECA points for ozone, with a pre-contingency at 135, at which point 'Doble Hoy No Circula' reaches holograms 0 and 00; that numeric threshold is press-reported and is deliberately kept out of the snippet. Direct fetch blocked (403).", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-afdaf4d2258b3ff4", "title": "El Financiero — 'Hoy No Circula: origen, historia y por que se instauro este programa en la CDMX'", "url": "https://www.elfinanciero.com.mx/cdmx/2023/03/27/hoy-no-circula-origen-historia-y-por-que-se-instauro-este-programa-en-la-cdmx/", "publisher": { "name": null, "domain": "elfinanciero.com.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-6154072a52ebdd2b", "clm-d81cf531abf232f9" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-14", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Origin detail: the programme began on 20 November 1989 as an emergency measure named 'Un Dia sin Auto' ('A Day Without a Car') during an ozone emergency, and was made mandatory and permanent by an accord published on 1 March 1990, alongside the introduction of biannual vehicle emissions verification. The exact 1990 date rests on Mexican press rather than on the Gaceta text, so the entry says only 'the following year'.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-6d20cebdd4a72790", "title": "adn40 — photo-enforcement cameras that sanction Hoy No Circula in CDMX (4 September 2025)", "url": "https://www.adn40.mx/ciudad/2025-09-04/puntos-camaras-fotomultas-sancionan-hoy-no-circula-cdmx-como-aplica-hoy", "publisher": { "name": null, "domain": "adn40.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-123a2c9c7699aada" ], "temporal": { "publishedAt": "2025-09-04", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-14", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "The camera question, media-grade only: 'Estos dispositivos no solo sancionan a quienes exceden la velocidad, tambien detectan conductores que circulan sin respetar las restricciones ambientales' ('These devices do not only sanction those exceeding the speed limit, they also detect drivers circulating without respecting the environmental restrictions'), on a network described as more than 140 fixed cameras and radars plus mobile units, after CDMX restored economic photo-fines alongside the 2019 points-based fotocivicas. No official source confirming camera detection of Hoy No Circula was reachable, so this is not claimed in the snippet.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-344cf108280f6545", "title": "Guerra and Millard-Ball, 'Getting around a license-plate ban: behavioral responses to Mexico City's driving restriction', Transportation Research Part D 55, 2017", "url": "https://www.sciencedirect.com/science/article/abs/pii/S1361920917303498", "publisher": { "name": null, "domain": "sciencedirect.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-d8a858260451ab03" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-14", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Peer-reviewed follow-up on how drivers evade the ban, including shifting trips onto lightly policed roads. Publisher page blocked (403) from this desk; listed for existence and topic. No figure in this entry rests on it.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } } ], "coverage": { "claimsTotal": 12, "claimsMapped": 12, "sourcesTotal": 9, "sourcesUsedByClaims": 9, "sourcesWithPublicationDate": 1, "sourcesWithArchive": 1, "sourcesWithExactLocator": 0, "sourcesWithContentHash": 0 }, "limits": [ "Publisher names and source languages have not yet been classified; domains are recorded without guessing.", "Existing source notes are descriptive locators, not page- or paragraph-exact citations.", "A missing archive, publication date or content hash is shown as null rather than inferred.", "The project-level evidence grade ranks the strongest source in the entry; it is not a truth score for every claim." ] } }, { "id": "2026-08-20-source-dates-b2", "createdAt": "2026-08-20T17:00:00Z", "effectiveAt": "2026-07-26", "changeType": "update", "summary": "Record the publication date of each source that states one; sources that publish no date are marked null.", "preparedBy": { "type": "automation", "label": "AI-assisted evidence preparation", "humanApproved": false }, "review": { "status": "unreviewed", "by": null, "date": null, "note": "Awaiting operator and domain-expert review; publication of this revision implies neither." }, "changes": [ { "operation": "replace", "path": "/snapshot/projectFingerprint", "summary": "Updated projectFingerprint to the current sourced project record." }, { "operation": "replace", "path": "/snapshot/sources", "summary": "Updated sources to the current sourced project record." } ], "snapshotHash": "sha256:631f25b603f98b9c05dd2dfee0c892717c1c38c99bfb13a7b1e22d938dc39f09", "snapshot": { "asOf": "2026-07-26", "projectFingerprint": "sha256:8b561f7456b978544c411a3a32831d63c825c5f3f55c732deaa024ad2b77d74d", "assurance": { "status": "unreviewed", "scope": "evidence-passport-revision", "statement": "AI-assisted structural preparation. This revision has not been reviewed by a human or subject-matter expert.", "machineChecks": [ "schema", "publication-diff-contract", "material-project-fingerprint", "claim-text-drift", "source-reference-resolution", "complete-source-dossier", "snapshot-hash" ] }, "projectState": { "status": "live", "outcome": "ongoing", "evidenceGrade": "peer-reviewed", "timeline": { "started": 1989, "ended": null } }, "governance": { "operator": "Secretaria del Medio Ambiente de la Ciudad de Mexico (SEDEMA), with the Comision Ambiental de la Megalopolis (CAMe) coordinating the metropolitan zone and traffic police enforcing on the street", "actorTypes": [ "city-government", "regional-government" ], "fundingModel": "public", "fundingDescription": null, "cost": null, "ownership": null, "decisionRights": null, "exitConditions": null }, "claims": [ { "id": "clm-c05142d557d70a65", "field": "impact", "text": "Davis (Journal of Political Economy 116(1), 2008) found 'across pollutants and specifications there is no evidence that the restrictions have improved air quality', together with evidence that the ban raised the total number of vehicles in circulation and shifted the fleet toward high-emission cars.", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24" ], "supportNote": "Two further peer-reviewed studies cited in the entry corroborate the null result and the second-car workaround.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-6154072a52ebdd2b", "field": "body", "text": "Mexico City started keeping cars off the road one weekday a week by the last digit of their plate in November 1989, after an ozone emergency, and made the rule permanent the following year", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24", "src-afdaf4d2258b3ff4" ], "supportNote": "Davis dates the programme to November 1989 and its permanence to the following year; El Financiero carries the same origin during an ozone emergency.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-d81cf531abf232f9", "field": "body", "text": "It began on 20 November 1989 as an emergency measure named ‘Un Día sin Auto’", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-afdaf4d2258b3ff4" ], "supportNote": "El Financiero: the programme began on 20 November 1989 as an emergency measure named 'Un Dia sin Auto' during an ozone emergency.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-ee48b27635074471", "field": "body", "text": "A compulsory emissions test every six months assigns each car a hologram, and that reading decides how hard the ban bites: holograms 00 and 0 drive every day, hologram 1 also rests two Saturdays a month, hologram 2 every Saturday", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-debbf8eec8ff1891", "src-7d81a556f40673ac" ], "supportNote": "CAMe's description of the programme carries the hologram tiers and which of them rest on Saturdays; SEDEMA is the operator page for the same rules.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-b110d027832a161a", "field": "body", "text": "When the metropolitan monitoring network pushes ozone past the contingency threshold the regional environment commission declares a ‘Fase I’ that pulls even exempt cars off the road", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ad142b48dbcb7470", "src-debbf8eec8ff1891" ], "supportNote": "CAMe declares the contingency and a Fase I declaration extends the driving ban to otherwise exempt vehicles.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-aaf51da274454a23", "field": "body", "text": "CAMe activated five ozone Fase I contingencies in 2025 alone", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ad142b48dbcb7470" ], "supportNote": "The government/CAMe record of ozone contingencies gives five Fase I activations in 2025.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-0b5f70ac48d9cee9", "field": "body", "text": "‘across pollutants and specifications there is no evidence that the restrictions have improved air quality’", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24" ], "supportNote": "Verbatim from the paper's abstract.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-31c3f86ab4d2e7aa", "field": "body", "text": "evidence that the ban raised the total number of vehicles in circulation and shifted the fleet toward high-emission cars", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24" ], "supportNote": "The same paper reports the increase in total vehicles and the shift toward high-emission cars.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-26c8718fff3952dd", "field": "body", "text": "an initial drop in car use followed by a rise in the household vehicle stock within eleven months", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-1aed7de45827ff4b" ], "supportNote": "Gallego, Montero and Salas measure an initial fall in car use followed by a rise in the household vehicle stock within eleven months.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-a2d6ea97cf37a835", "field": "body", "text": "the July 2008 Saturday extension had virtually no discernible effect across eight pollutants, and no sign that drivers switched to metro, bus or light rail", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-78b678356a3b5670" ], "supportNote": "Davis 2017 tests the Saturday extension across eight pollutants and finds virtually no discernible effect and no modal shift.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-d8a858260451ab03", "field": "body", "text": "drivers shifting trips onto lightly policed roads", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-344cf108280f6545" ], "supportNote": "Guerra and Millard-Ball examine behavioural responses to the ban, including trips shifted onto lightly policed roads. Cited from the abstract; the publisher page was blocked from this desk.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-123a2c9c7699aada", "field": "body", "text": "Press reporting describes photo-enforcement cameras in Mexico City that sanction Hoy No Circula violations as well as speeding", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-6d20cebdd4a72790" ], "supportNote": "Media-grade only: adn40 reports cameras in CDMX that sanction Hoy No Circula violations as well as speeding. No operator document confirms the scale.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } } ], "sources": [ { "id": "src-ace305ebc8ebcd24", "title": "Davis, 'The Effect of Driving Restrictions on Air Quality in Mexico City', Journal of Political Economy 116(1), 2008, pp. 38-81", "url": "https://econpapers.repec.org/article/ucpjpolec/v_3a116_3ay_3a2008_3ai_3a1_3ap_3a38-81.htm", "publisher": { "name": null, "domain": "econpapers.repec.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-c05142d557d70a65", "clm-6154072a52ebdd2b", "clm-0b5f70ac48d9cee9", "clm-31c3f86ab4d2e7aa" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-20", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "The load-bearing null result, abstract verbatim: 'In 1989, the government of Mexico City introduced a program, Hoy No Circula, that bans most drivers from using their vehicles one weekday per week on the basis of the last digit of the vehicle's license plate... Across pollutants and specifications there is no evidence that the restrictions have improved air quality. Evidence from additional sources indicates that the restrictions led to an increase in the total number of vehicles in circulation as well as a change in composition toward high-emissions vehicles.' Publisher page journals.uchicago.edu/doi/10.1086/529398; the author's own copy is at faculty.haas.berkeley.edu/ldavis/Davis%20JPE%202008.pdf but did not render from this desk, so the abstract was verified against this indexed mirror.", "exact": false }, "preservation": { "archiveUrl": "https://web.archive.org/web/20240428163441/https://econpapers.repec.org/article/ucpjpolec/v_3a116_3ay_3a2008_3ai_3a1_3ap_3a38-81.htm", "archivedAt": "2024-04-28", "contentHash": null, "status": "archive-linked" } }, { "id": "src-78b678356a3b5670", "title": "Davis, 'Saturday Driving Restrictions Fail to Improve Air Quality in Mexico City', Scientific Reports 7:41652, 2017", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC5289101/", "publisher": { "name": null, "domain": "pmc.ncbi.nlm.nih.gov", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-a2d6ea97cf37a835" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-20", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Dates the Saturday extension and grades it: 'Mexico City's driving restrictions were expanded to include Saturdays on July 5th, 2008.' and 'Overall, there is little evidence that the program expansion improved air quality.' Also the sentence this entry uses on enforcement: 'City police vigorously enforce the restrictions and vehicles violating the ban are easy to spot. Drivers caught violating the rules must pay a hefty fine and their vehicles are impounded for 48 hours.'", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-1aed7de45827ff4b", "title": "Gallego, Montero and Salas, 'The effect of transport policies on car use: Evidence from Latin American cities', Journal of Public Economics 107, 2013, pp. 47-62", "url": "https://econpapers.repec.org/RePEc:eee:pubeco:v:107:y:2013:i:c:p:47-62", "publisher": { "name": null, "domain": "econpapers.repec.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-26c8718fff3952dd" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-20", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Independently dates the programme to November 1989 and measures the second-car response: an expected short-run fall in car use followed by a rapid rise in the household vehicle stock inside eleven months, with a transport cost put at about 5 per cent of the value of the vehicle stock at implementation. Cited for the rebound, not for any air-quality figure.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-7d81a556f40673ac", "title": "SEDEMA, Ciudad de Mexico — Programa Hoy No Circula", "url": "https://sedema.cdmx.gob.mx/programas/programa/hoy-no-circula", "publisher": { "name": null, "domain": "sedema.cdmx.gob.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-ee48b27635074471" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-20", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "The operator's own programme page and the correct citation for the current rules. Direct fetch returned 503 from this desk on 2026-07-26; the rules were corroborated against the CAMe description and the 2026 press cited below, which agree on hours, coverage and hologram tiers.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-debbf8eec8ff1891", "title": "Comision Ambiental de la Megalopolis — 'El Programa Hoy No Circula que aplica en la Zona Metropolitana del Valle de Mexico'", "url": "https://www.gob.mx/comisionambiental/prensa/el-programa-hoy-no-circula-que-aplica-en-la-zona-metropolitana-del-valle-de-mexico", "publisher": { "name": null, "domain": "gob.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-ee48b27635074471", "clm-b110d027832a161a" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-20", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "The metropolitan authority's own description, carrying the coverage and hours used in the snippet: 'Aplica en las 16 alcaldias de la Ciudad de Mexico y en 18 municipios conurbados del Estado de Mexico, de lunes a sabado de 5:00 a 22:00 h' ('It applies in the 16 boroughs of Mexico City and in 18 adjoining municipalities of the State of Mexico, Monday to Saturday from 5:00 to 22:00'), and the hologram rule: 'Los vehiculos con holograma 1 no circulan dos sabados del mes segun su terminacion, mientras que los vehiculos con holograma 2 no circulan ningun sabado del mes' ('Hologram 1 vehicles do not drive on two Saturdays a month according to their plate ending, while hologram 2 vehicles do not drive on any Saturday'). Direct fetch blocked (403); the carrying sentences were confirmed by search.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-ad142b48dbcb7470", "title": "Gobierno de Mexico / CAMe — Fase I de contingencia ambiental atmosferica por ozono en la ZMVM", "url": "https://www.gob.mx/comisionambiental/prensa/se-mantiene-la-fase-i-de-contingencia-ambiental-atmosferica-por-ozono-en-la-zona-metropolitana-del-valle-de-mexico-424546", "publisher": { "name": null, "domain": "gob.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-b110d027832a161a", "clm-aaf51da274454a23" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-20", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Establishes who declares a contingency and that a declaration extends the driving ban. CAMe activated five ozone Fase I contingencies in 2025 alone (26 February, 18 March, 1, 23 and 25 April). The activation threshold is reported by Mexican press as 150 IMECA points for ozone, with a pre-contingency at 135, at which point 'Doble Hoy No Circula' reaches holograms 0 and 00; that numeric threshold is press-reported and is deliberately kept out of the snippet. Direct fetch blocked (403).", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-afdaf4d2258b3ff4", "title": "El Financiero — 'Hoy No Circula: origen, historia y por que se instauro este programa en la CDMX'", "url": "https://www.elfinanciero.com.mx/cdmx/2023/03/27/hoy-no-circula-origen-historia-y-por-que-se-instauro-este-programa-en-la-cdmx/", "publisher": { "name": null, "domain": "elfinanciero.com.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-6154072a52ebdd2b", "clm-d81cf531abf232f9" ], "temporal": { "publishedAt": "2023-03-27", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-20", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Origin detail: the programme began on 20 November 1989 as an emergency measure named 'Un Dia sin Auto' ('A Day Without a Car') during an ozone emergency, and was made mandatory and permanent by an accord published on 1 March 1990, alongside the introduction of biannual vehicle emissions verification. The exact 1990 date rests on Mexican press rather than on the Gaceta text, so the entry says only 'the following year'.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-6d20cebdd4a72790", "title": "adn40 — photo-enforcement cameras that sanction Hoy No Circula in CDMX (4 September 2025)", "url": "https://www.adn40.mx/ciudad/2025-09-04/puntos-camaras-fotomultas-sancionan-hoy-no-circula-cdmx-como-aplica-hoy", "publisher": { "name": null, "domain": "adn40.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-123a2c9c7699aada" ], "temporal": { "publishedAt": "2025-09-04", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-20", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "The camera question, media-grade only: 'Estos dispositivos no solo sancionan a quienes exceden la velocidad, tambien detectan conductores que circulan sin respetar las restricciones ambientales' ('These devices do not only sanction those exceeding the speed limit, they also detect drivers circulating without respecting the environmental restrictions'), on a network described as more than 140 fixed cameras and radars plus mobile units, after CDMX restored economic photo-fines alongside the 2019 points-based fotocivicas. No official source confirming camera detection of Hoy No Circula was reachable, so this is not claimed in the snippet.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-344cf108280f6545", "title": "Guerra and Millard-Ball, 'Getting around a license-plate ban: behavioral responses to Mexico City's driving restriction', Transportation Research Part D 55, 2017", "url": "https://www.sciencedirect.com/science/article/abs/pii/S1361920917303498", "publisher": { "name": null, "domain": "sciencedirect.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-d8a858260451ab03" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-20", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Peer-reviewed follow-up on how drivers evade the ban, including shifting trips onto lightly policed roads. Publisher page blocked (403) from this desk; listed for existence and topic. No figure in this entry rests on it.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } } ], "coverage": { "claimsTotal": 12, "claimsMapped": 12, "sourcesTotal": 9, "sourcesUsedByClaims": 9, "sourcesWithPublicationDate": 2, "sourcesWithArchive": 1, "sourcesWithExactLocator": 0, "sourcesWithContentHash": 0 }, "limits": [ "Publisher names and source languages have not yet been classified; domains are recorded without guessing.", "Existing source notes are descriptive locators, not page- or paragraph-exact citations.", "A missing archive, publication date or content hash is shown as null rather than inferred.", "The project-level evidence grade ranks the strongest source in the entry; it is not a truth score for every claim." ] } }, { "id": "2026-08-20-source-dates-r2", "createdAt": "2026-08-21T09:00:00Z", "effectiveAt": "2026-07-26", "changeType": "update", "summary": "Record the publication date of each source that states one; sources that publish no date are marked null.", "preparedBy": { "type": "automation", "label": "AI-assisted evidence preparation", "humanApproved": false }, "review": { "status": "unreviewed", "by": null, "date": null, "note": "Awaiting operator and domain-expert review; publication of this revision implies neither." }, "changes": [ { "operation": "replace", "path": "/snapshot/projectFingerprint", "summary": "Updated projectFingerprint to the current sourced project record." }, { "operation": "replace", "path": "/snapshot/sources", "summary": "Updated sources to the current sourced project record." } ], "snapshotHash": "sha256:0d4b5d16e637a304290540b651f6dabe06dd35332a69292480e71279412ca6b6", "snapshot": { "asOf": "2026-07-26", "projectFingerprint": "sha256:bd8223469345810b535c8cd7c363ba543b9a741c8e0f62b9985c6bb83cc0a360", "assurance": { "status": "unreviewed", "scope": "evidence-passport-revision", "statement": "AI-assisted structural preparation. This revision has not been reviewed by a human or subject-matter expert.", "machineChecks": [ "schema", "publication-diff-contract", "material-project-fingerprint", "claim-text-drift", "source-reference-resolution", "complete-source-dossier", "snapshot-hash" ] }, "projectState": { "status": "live", "outcome": "ongoing", "evidenceGrade": "peer-reviewed", "timeline": { "started": 1989, "ended": null } }, "governance": { "operator": "Secretaria del Medio Ambiente de la Ciudad de Mexico (SEDEMA), with the Comision Ambiental de la Megalopolis (CAMe) coordinating the metropolitan zone and traffic police enforcing on the street", "actorTypes": [ "city-government", "regional-government" ], "fundingModel": "public", "fundingDescription": null, "cost": null, "ownership": null, "decisionRights": null, "exitConditions": null }, "claims": [ { "id": "clm-c05142d557d70a65", "field": "impact", "text": "Davis (Journal of Political Economy 116(1), 2008) found 'across pollutants and specifications there is no evidence that the restrictions have improved air quality', together with evidence that the ban raised the total number of vehicles in circulation and shifted the fleet toward high-emission cars.", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24" ], "supportNote": "Two further peer-reviewed studies cited in the entry corroborate the null result and the second-car workaround.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-6154072a52ebdd2b", "field": "body", "text": "Mexico City started keeping cars off the road one weekday a week by the last digit of their plate in November 1989, after an ozone emergency, and made the rule permanent the following year", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24", "src-afdaf4d2258b3ff4" ], "supportNote": "Davis dates the programme to November 1989 and its permanence to the following year; El Financiero carries the same origin during an ozone emergency.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-d81cf531abf232f9", "field": "body", "text": "It began on 20 November 1989 as an emergency measure named ‘Un Día sin Auto’", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-afdaf4d2258b3ff4" ], "supportNote": "El Financiero: the programme began on 20 November 1989 as an emergency measure named 'Un Dia sin Auto' during an ozone emergency.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-ee48b27635074471", "field": "body", "text": "A compulsory emissions test every six months assigns each car a hologram, and that reading decides how hard the ban bites: holograms 00 and 0 drive every day, hologram 1 also rests two Saturdays a month, hologram 2 every Saturday", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-debbf8eec8ff1891", "src-7d81a556f40673ac" ], "supportNote": "CAMe's description of the programme carries the hologram tiers and which of them rest on Saturdays; SEDEMA is the operator page for the same rules.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-b110d027832a161a", "field": "body", "text": "When the metropolitan monitoring network pushes ozone past the contingency threshold the regional environment commission declares a ‘Fase I’ that pulls even exempt cars off the road", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ad142b48dbcb7470", "src-debbf8eec8ff1891" ], "supportNote": "CAMe declares the contingency and a Fase I declaration extends the driving ban to otherwise exempt vehicles.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-aaf51da274454a23", "field": "body", "text": "CAMe activated five ozone Fase I contingencies in 2025 alone", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ad142b48dbcb7470" ], "supportNote": "The government/CAMe record of ozone contingencies gives five Fase I activations in 2025.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-0b5f70ac48d9cee9", "field": "body", "text": "‘across pollutants and specifications there is no evidence that the restrictions have improved air quality’", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24" ], "supportNote": "Verbatim from the paper's abstract.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-31c3f86ab4d2e7aa", "field": "body", "text": "evidence that the ban raised the total number of vehicles in circulation and shifted the fleet toward high-emission cars", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24" ], "supportNote": "The same paper reports the increase in total vehicles and the shift toward high-emission cars.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-26c8718fff3952dd", "field": "body", "text": "an initial drop in car use followed by a rise in the household vehicle stock within eleven months", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-1aed7de45827ff4b" ], "supportNote": "Gallego, Montero and Salas measure an initial fall in car use followed by a rise in the household vehicle stock within eleven months.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-a2d6ea97cf37a835", "field": "body", "text": "the July 2008 Saturday extension had virtually no discernible effect across eight pollutants, and no sign that drivers switched to metro, bus or light rail", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-78b678356a3b5670" ], "supportNote": "Davis 2017 tests the Saturday extension across eight pollutants and finds virtually no discernible effect and no modal shift.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-d8a858260451ab03", "field": "body", "text": "drivers shifting trips onto lightly policed roads", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-344cf108280f6545" ], "supportNote": "Guerra and Millard-Ball examine behavioural responses to the ban, including trips shifted onto lightly policed roads. Cited from the abstract; the publisher page was blocked from this desk.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-123a2c9c7699aada", "field": "body", "text": "Press reporting describes photo-enforcement cameras in Mexico City that sanction Hoy No Circula violations as well as speeding", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-6d20cebdd4a72790" ], "supportNote": "Media-grade only: adn40 reports cameras in CDMX that sanction Hoy No Circula violations as well as speeding. No operator document confirms the scale.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } } ], "sources": [ { "id": "src-ace305ebc8ebcd24", "title": "Davis, 'The Effect of Driving Restrictions on Air Quality in Mexico City', Journal of Political Economy 116(1), 2008, pp. 38-81", "url": "https://econpapers.repec.org/article/ucpjpolec/v_3a116_3ay_3a2008_3ai_3a1_3ap_3a38-81.htm", "publisher": { "name": null, "domain": "econpapers.repec.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-c05142d557d70a65", "clm-6154072a52ebdd2b", "clm-0b5f70ac48d9cee9", "clm-31c3f86ab4d2e7aa" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-21", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "The load-bearing null result, abstract verbatim: 'In 1989, the government of Mexico City introduced a program, Hoy No Circula, that bans most drivers from using their vehicles one weekday per week on the basis of the last digit of the vehicle's license plate... Across pollutants and specifications there is no evidence that the restrictions have improved air quality. Evidence from additional sources indicates that the restrictions led to an increase in the total number of vehicles in circulation as well as a change in composition toward high-emissions vehicles.' Publisher page journals.uchicago.edu/doi/10.1086/529398; the author's own copy is at faculty.haas.berkeley.edu/ldavis/Davis%20JPE%202008.pdf but did not render from this desk, so the abstract was verified against this indexed mirror.", "exact": false }, "preservation": { "archiveUrl": "https://web.archive.org/web/20240428163441/https://econpapers.repec.org/article/ucpjpolec/v_3a116_3ay_3a2008_3ai_3a1_3ap_3a38-81.htm", "archivedAt": "2024-04-28", "contentHash": null, "status": "archive-linked" } }, { "id": "src-78b678356a3b5670", "title": "Davis, 'Saturday Driving Restrictions Fail to Improve Air Quality in Mexico City', Scientific Reports 7:41652, 2017", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC5289101/", "publisher": { "name": null, "domain": "pmc.ncbi.nlm.nih.gov", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-a2d6ea97cf37a835" ], "temporal": { "publishedAt": "2017-02-02", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-21", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Dates the Saturday extension and grades it: 'Mexico City's driving restrictions were expanded to include Saturdays on July 5th, 2008.' and 'Overall, there is little evidence that the program expansion improved air quality.' Also the sentence this entry uses on enforcement: 'City police vigorously enforce the restrictions and vehicles violating the ban are easy to spot. Drivers caught violating the rules must pay a hefty fine and their vehicles are impounded for 48 hours.'", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-1aed7de45827ff4b", "title": "Gallego, Montero and Salas, 'The effect of transport policies on car use: Evidence from Latin American cities', Journal of Public Economics 107, 2013, pp. 47-62", "url": "https://econpapers.repec.org/RePEc:eee:pubeco:v:107:y:2013:i:c:p:47-62", "publisher": { "name": null, "domain": "econpapers.repec.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-26c8718fff3952dd" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-21", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Independently dates the programme to November 1989 and measures the second-car response: an expected short-run fall in car use followed by a rapid rise in the household vehicle stock inside eleven months, with a transport cost put at about 5 per cent of the value of the vehicle stock at implementation. Cited for the rebound, not for any air-quality figure.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-7d81a556f40673ac", "title": "SEDEMA, Ciudad de Mexico — Programa Hoy No Circula", "url": "https://sedema.cdmx.gob.mx/programas/programa/hoy-no-circula", "publisher": { "name": null, "domain": "sedema.cdmx.gob.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-ee48b27635074471" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-21", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "The operator's own programme page and the correct citation for the current rules. Direct fetch returned 503 from this desk on 2026-07-26; the rules were corroborated against the CAMe description and the 2026 press cited below, which agree on hours, coverage and hologram tiers.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-debbf8eec8ff1891", "title": "Comision Ambiental de la Megalopolis — 'El Programa Hoy No Circula que aplica en la Zona Metropolitana del Valle de Mexico'", "url": "https://www.gob.mx/comisionambiental/prensa/el-programa-hoy-no-circula-que-aplica-en-la-zona-metropolitana-del-valle-de-mexico", "publisher": { "name": null, "domain": "gob.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-ee48b27635074471", "clm-b110d027832a161a" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-21", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "The metropolitan authority's own description, carrying the coverage and hours used in the snippet: 'Aplica en las 16 alcaldias de la Ciudad de Mexico y en 18 municipios conurbados del Estado de Mexico, de lunes a sabado de 5:00 a 22:00 h' ('It applies in the 16 boroughs of Mexico City and in 18 adjoining municipalities of the State of Mexico, Monday to Saturday from 5:00 to 22:00'), and the hologram rule: 'Los vehiculos con holograma 1 no circulan dos sabados del mes segun su terminacion, mientras que los vehiculos con holograma 2 no circulan ningun sabado del mes' ('Hologram 1 vehicles do not drive on two Saturdays a month according to their plate ending, while hologram 2 vehicles do not drive on any Saturday'). Direct fetch blocked (403); the carrying sentences were confirmed by search.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-ad142b48dbcb7470", "title": "Gobierno de Mexico / CAMe — Fase I de contingencia ambiental atmosferica por ozono en la ZMVM", "url": "https://www.gob.mx/comisionambiental/prensa/se-mantiene-la-fase-i-de-contingencia-ambiental-atmosferica-por-ozono-en-la-zona-metropolitana-del-valle-de-mexico-424546", "publisher": { "name": null, "domain": "gob.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-b110d027832a161a", "clm-aaf51da274454a23" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-21", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Establishes who declares a contingency and that a declaration extends the driving ban. CAMe activated five ozone Fase I contingencies in 2025 alone (26 February, 18 March, 1, 23 and 25 April). The activation threshold is reported by Mexican press as 150 IMECA points for ozone, with a pre-contingency at 135, at which point 'Doble Hoy No Circula' reaches holograms 0 and 00; that numeric threshold is press-reported and is deliberately kept out of the snippet. Direct fetch blocked (403).", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-afdaf4d2258b3ff4", "title": "El Financiero — 'Hoy No Circula: origen, historia y por que se instauro este programa en la CDMX'", "url": "https://www.elfinanciero.com.mx/cdmx/2023/03/27/hoy-no-circula-origen-historia-y-por-que-se-instauro-este-programa-en-la-cdmx/", "publisher": { "name": null, "domain": "elfinanciero.com.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-6154072a52ebdd2b", "clm-d81cf531abf232f9" ], "temporal": { "publishedAt": "2023-03-27", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-21", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Origin detail: the programme began on 20 November 1989 as an emergency measure named 'Un Dia sin Auto' ('A Day Without a Car') during an ozone emergency, and was made mandatory and permanent by an accord published on 1 March 1990, alongside the introduction of biannual vehicle emissions verification. The exact 1990 date rests on Mexican press rather than on the Gaceta text, so the entry says only 'the following year'.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-6d20cebdd4a72790", "title": "adn40 — photo-enforcement cameras that sanction Hoy No Circula in CDMX (4 September 2025)", "url": "https://www.adn40.mx/ciudad/2025-09-04/puntos-camaras-fotomultas-sancionan-hoy-no-circula-cdmx-como-aplica-hoy", "publisher": { "name": null, "domain": "adn40.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-123a2c9c7699aada" ], "temporal": { "publishedAt": "2025-09-04", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-21", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "The camera question, media-grade only: 'Estos dispositivos no solo sancionan a quienes exceden la velocidad, tambien detectan conductores que circulan sin respetar las restricciones ambientales' ('These devices do not only sanction those exceeding the speed limit, they also detect drivers circulating without respecting the environmental restrictions'), on a network described as more than 140 fixed cameras and radars plus mobile units, after CDMX restored economic photo-fines alongside the 2019 points-based fotocivicas. No official source confirming camera detection of Hoy No Circula was reachable, so this is not claimed in the snippet.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-344cf108280f6545", "title": "Guerra and Millard-Ball, 'Getting around a license-plate ban: behavioral responses to Mexico City's driving restriction', Transportation Research Part D 55, 2017", "url": "https://www.sciencedirect.com/science/article/abs/pii/S1361920917303498", "publisher": { "name": null, "domain": "sciencedirect.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-d8a858260451ab03" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-07-26", "dossierCreatedAt": "2026-08-21", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Peer-reviewed follow-up on how drivers evade the ban, including shifting trips onto lightly policed roads. Publisher page blocked (403) from this desk; listed for existence and topic. No figure in this entry rests on it.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } } ], "coverage": { "claimsTotal": 12, "claimsMapped": 12, "sourcesTotal": 9, "sourcesUsedByClaims": 9, "sourcesWithPublicationDate": 3, "sourcesWithArchive": 1, "sourcesWithExactLocator": 0, "sourcesWithContentHash": 0 }, "limits": [ "Publisher names and source languages have not yet been classified; domains are recorded without guessing.", "Existing source notes are descriptive locators, not page- or paragraph-exact citations.", "A missing archive, publication date or content hash is shown as null rather than inferred.", "The project-level evidence grade ranks the strongest source in the entry; it is not a truth score for every claim." ] } }, { "id": "2026-08-27-landmark-p6-uplift", "createdAt": "2026-08-27T20:01:00Z", "effectiveAt": "2026-08-27", "changeType": "update", "summary": "Landmark-of-the-week editorial re-verification: full-field claim coverage (12 to 28 claims, every claim with a locator or an explicit reason), every source dated or explicitly null, six sources added (El Universal chronology and live rules pages, El Horizonte, the open Gallego working paper, the Guerra and Millard-Ball preprint), and three corrections — the 'Un Dia sin Auto' name belongs to a 1984 voluntary campaign rather than the 1989 decree, the five 2025 contingencies are re-anchored to a source that actually carries them, and Guerra and Millard-Ball's rejection of the second-car explanation is now presented as a contradiction in the record.", "preparedBy": { "type": "automation", "label": "AI-assisted evidence preparation", "humanApproved": false }, "review": { "status": "unreviewed", "by": null, "date": null, "note": "Awaiting operator and domain-expert review; publication of this revision implies neither." }, "changes": [ { "operation": "replace", "path": "/snapshot/projectFingerprint", "summary": "Updated projectFingerprint to the current sourced project record." }, { "operation": "replace", "path": "/snapshot/asOf", "summary": "Updated asOf to the current sourced project record." }, { "operation": "replace", "path": "/snapshot/claims", "summary": "Updated claims to the current sourced project record." }, { "operation": "replace", "path": "/snapshot/sources", "summary": "Updated sources to the current sourced project record." } ], "snapshotHash": "sha256:bc2c756c15b2edfcca5b6c2be6e16eeb1253facc880e865d59959eb5e36c8f8d", "snapshot": { "asOf": "2026-08-27", "projectFingerprint": "sha256:a2cad02324fc35283786aa1d5911addcfad5773b65bde69c8ba809a76f264f1f", "assurance": { "status": "unreviewed", "scope": "evidence-passport-revision", "statement": "AI-assisted structural preparation. This revision has not been reviewed by a human or subject-matter expert.", "machineChecks": [ "schema", "publication-diff-contract", "material-project-fingerprint", "claim-text-drift", "source-reference-resolution", "complete-source-dossier", "snapshot-hash" ] }, "projectState": { "status": "live", "outcome": "ongoing", "evidenceGrade": "peer-reviewed", "timeline": { "started": 1989, "ended": null } }, "governance": { "operator": "Secretaria del Medio Ambiente de la Ciudad de Mexico (SEDEMA), with the Comision Ambiental de la Megalopolis (CAMe) coordinating the metropolitan zone and traffic police enforcing on the street", "actorTypes": [ "city-government", "regional-government" ], "fundingModel": "public", "fundingDescription": null, "cost": null, "ownership": null, "decisionRights": null, "exitConditions": null }, "claims": [ { "id": "clm-66cd2822e489894f", "field": "snippet", "text": "started keeping cars off the road one weekday a week by the last digit of their plate in November 1989, after an ozone emergency", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-78b678356a3b5670", "src-ace305ebc8ebcd24", "src-afdaf4d2258b3ff4" ], "supportNote": "Davis (2017) carries the start and the motive in one sentence; Davis (2008) describes the plate-digit weekday mechanism; El Financiero dates the start to 20 November 1989 during an environmental emergency.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-4a03dd104b995183", "field": "snippet", "text": "made the rule permanent the following year", "statementKind": "descriptive", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-eae82745034bd9a6" ], "supportNote": "El Universal's chronology, 1990 item: the programme was extended permanently, no longer only for the winter season.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-c19d3297f5e262b6", "field": "snippet", "text": "A compulsory emissions test every six months assigns each car a hologram", "statementKind": "descriptive", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-8d6241d5417f2cf6", "src-eae82745034bd9a6" ], "supportNote": "El Universal's verification page carries the semester rhythm — each sticker colour has two verification windows a year, and hologram 0 is listed with six-month validity ('vigencia semestral'); the chronology dates the verification programme itself to 1990.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-f07d03e622030cbc", "field": "snippet", "text": "holograms 00 and 0 drive every day, hologram 1 also rests two Saturdays a month, hologram 2 every Saturday", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-debbf8eec8ff1891", "src-7d81a556f40673ac" ], "supportNote": "CAMe's description of the programme carries the hologram tiers and which of them rest on Saturdays; SEDEMA is the operator page for the same rules.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-f8ae7d9a3609a2c4", "field": "snippet", "text": "Saturdays were added on 5 July 2008", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-78b678356a3b5670", "src-eae82745034bd9a6" ], "supportNote": "Davis (2017) dates the extension exactly; El Universal's chronology, written days before the launch, announces the same date.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-a7148f006fd68da9", "field": "snippet", "text": "when the metropolitan monitoring network pushes ozone past the contingency threshold the regional environment commission declares a 'Fase I' that pulls even exempt cars off the road", "statementKind": "descriptive", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-ad142b48dbcb7470", "src-988c68fa7ef99f12" ], "supportNote": "The CAMe communique shows the commission declaring and maintaining a Fase I whose restrictions reach even normally exempt hologram 0 and 00 cars; El Horizonte reports the trigger reading (159 ppb of ozone) behind one such declaration.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-3918e7e8c63dfaa2", "field": "snippet", "text": "Thirty-seven years on, peer-reviewed evaluations have still not found that the air got cleaner", "statementKind": "descriptive", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24", "src-78b678356a3b5670" ], "supportNote": "Davis (2008) found no evidence of improved air quality across pollutants and specifications; Davis (2017) found the Saturday extension had virtually no discernible effect. The 2017 behavioural study by Guerra and Millard-Ball reports no air-quality gain either.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-c05142d557d70a65", "field": "impact", "text": "Davis (Journal of Political Economy 116(1), 2008) found 'across pollutants and specifications there is no evidence that the restrictions have improved air quality', together with evidence that the ban raised the total number of vehicles in circulation and shifted the fleet toward high-emission cars.", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24" ], "supportNote": "The abstract carries both halves verbatim: the null result across pollutants and specifications, and the evidence of more vehicles in circulation with a shift toward high-emissions vehicles.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-0bae69017f650c62", "field": "impact", "text": "Davis (Scientific Reports 7:41652, 2017) found the July 2008 Saturday extension had virtually no discernible effect across eight pollutants, and no sign that drivers switched to metro, bus or light rail.", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-78b678356a3b5670" ], "supportNote": "The paper states both findings: virtually no discernible effect on pollution levels across eight major pollutants, and no evidence from subway, bus and light-rail ridership that drivers switched to lower-emitting transport.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-45ffb8fffa657de4", "field": "impact", "text": "Gallego, Montero and Salas (Journal of Public Economics 107, 2013) measured the workaround directly: an initial drop in car use followed by a rise in the household vehicle stock within eleven months.", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-1aed7de45827ff4b", "src-7689b587dad366e5" ], "supportNote": "The published abstract carries the direction ('more cars on the road' and rapid household stock adjustment); the open working-paper abstract carries the figure verbatim: 'an expected short-run response followed by a rapid (before 11 months) increase in the stock of vehicles.'", "caveat": "Guerra and Millard-Ball (2017) later rejected the finding that households adapt to the ban mainly through second-car purchases; the two measurements stand unreconciled in the literature.", "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-c02b4903279b2b8c", "field": "impact", "text": "Guerra and Millard-Ball (Transportation Research Part D 55, 2017) confirmed the limited influence on driving but rejected the second-car explanation, finding most households instead shuffle trips to the days their car may drive.", "statementKind": "quantitative", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-12e4c5d7271cd7b2", "src-344cf108280f6545" ], "supportNote": "The preprint's abstract and highlights carry all three parts: 'Confirms findings that Hoy No Circula had a limited influence on driving', 'we reject the prevailing theory that its lack of success is due to perverse incentives for households to buy second cars', and 'Finds that households avoid ban by shuffling weekly travel routines.'", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-b6e0cd5194c879bb", "field": "lesson", "text": "Ration driving by plate digit and the trips find their way back — the studies disagree only on how: two measured households buying a second, usually older, car; the most recent finds most households simply shuffling trips to unrestricted days", "statementKind": "descriptive", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24", "src-1aed7de45827ff4b", "src-12e4c5d7271cd7b2" ], "supportNote": "Davis (2008) found more vehicles in circulation and a shift toward high-emissions cars; Gallego, Montero and Salas measured the household stock rising within eleven months; Guerra and Millard-Ball reject the second-car theory and find day-shuffling instead.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-9775dc12820fd6fd", "field": "lesson", "text": "One of the oldest and best-known schemes of its genre carries four peer-reviewed studies, and not one of them reports that it did what it was built to do", "statementKind": "descriptive", "textMode": "verbatim-from-project-record", "mappingStatus": "mapped", "sourceRefs": [ "src-78b678356a3b5670", "src-ace305ebc8ebcd24", "src-1aed7de45827ff4b", "src-344cf108280f6545" ], "supportNote": "Davis (2017) calls Mexico City 'home to one of the oldest and best-known driving restriction policies'. The four studies cited by this entry report a null air result, a fleet shifted older, a household stock rebound, and behavioural avoidance — none reports cleaner air.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-6154072a52ebdd2b", "field": "body", "text": "Mexico City started keeping cars off the road one weekday a week by the last digit of their plate in November 1989, after an ozone emergency, and made the rule permanent the following year", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24", "src-afdaf4d2258b3ff4", "src-eae82745034bd9a6" ], "supportNote": "Davis (2008) carries the plate-digit weekday mechanism; El Financiero dates the start to 20 November 1989 during an environmental emergency; El Universal's chronology carries the 1990 permanence.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-a86267d740091154", "field": "body", "text": "an ecologist group had launched a voluntary ‘Un Día sin Auto’, a day without the car, back in 1984", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-eae82745034bd9a6" ], "supportNote": "El Universal's chronology, 1984 item: the citizens' initiative 'Un día Sin Auto', promoted by the ecologist group 'Mejora tu Ciudad', proposing not to use the car one day a week.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-5bc4e82d9aa17579", "field": "body", "text": "it began on 20 November 1989 as a winter-season measure", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-afdaf4d2258b3ff4", "src-eae82745034bd9a6" ], "supportNote": "El Financiero carries the exact start date during an environmental emergency; El Universal's chronology says the official 1989 programme applied to the winter season, when pollution levels are higher.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-da2d346b58597ddb", "field": "body", "text": "in 1990 it was made permanent, with the vehicle-verification programme established alongside it", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-eae82745034bd9a6" ], "supportNote": "El Universal's chronology, 1990 item, carries both: the programme extended permanently beyond the winter season, and the vehicle-verification programme established.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-ee48b27635074471", "field": "body", "text": "A compulsory emissions test every six months assigns each car a hologram, and that reading decides how hard the ban bites: holograms 00 and 0 drive every day, hologram 1 also rests two Saturdays a month, hologram 2 every Saturday", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-debbf8eec8ff1891", "src-8d6241d5417f2cf6", "src-7d81a556f40673ac" ], "supportNote": "CAMe's description of the programme carries the hologram tiers and which of them rest on Saturdays; El Universal's verification page carries the six-month rhythm; SEDEMA is the operator page for the same rules.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-b110d027832a161a", "field": "body", "text": "When the metropolitan monitoring network pushes ozone past the contingency threshold the regional environment commission declares a ‘Fase I’ that pulls even exempt cars off the road", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ad142b48dbcb7470", "src-988c68fa7ef99f12" ], "supportNote": "The CAMe communique shows the commission declaring and maintaining a Fase I whose restrictions reach even normally exempt hologram 0 and 00 cars; El Horizonte reports the trigger reading behind one such declaration.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-7930dd5c009face8", "field": "body", "text": "CAMe activated five ozone Fase I contingencies in the first four months of 2025 alone", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-988c68fa7ef99f12" ], "supportNote": "El Horizonte, reporting the 25 April 2025 activation: 'Esta es la quinta contingencia ambiental por ozono tras las del 26 de febrero, 18 de marzo, 1 de abril y 23 de abril' — the fifth ozone contingency of the year, after 26 February, 18 March, 1 April and 23 April.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-a034516d71a831fc", "field": "body", "text": "the mechanism was still firing the following spring, holding a Fase I in place through a Sunday in April 2026", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ad142b48dbcb7470" ], "supportNote": "The CAMe communique of 25 April 2026 maintains the Fase I ozone contingency and its measures 'para el día de mañana, domingo 26 de abril del 2026' — for the following day, Sunday 26 April 2026.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-0b5f70ac48d9cee9", "field": "body", "text": "‘across pollutants and specifications there is no evidence that the restrictions have improved air quality’", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24" ], "supportNote": "Verbatim from the paper's abstract.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-31c3f86ab4d2e7aa", "field": "body", "text": "evidence that the ban raised the total number of vehicles in circulation and shifted the fleet toward high-emission cars", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-ace305ebc8ebcd24" ], "supportNote": "The abstract states: 'the restrictions led to an increase in the total number of vehicles in circulation as well as a change in composition toward high-emissions vehicles.'", "caveat": "Guerra and Millard-Ball (2017) reject the finding that households adapt to the ban mainly by buying additional cars; the disagreement is presented later on this page.", "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-26c8718fff3952dd", "field": "body", "text": "an initial drop in car use followed by a rise in the household vehicle stock within eleven months", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-1aed7de45827ff4b", "src-7689b587dad366e5" ], "supportNote": "The open working-paper abstract carries the figure verbatim: 'an expected short-run response followed by a rapid (before 11 months) increase in the stock of vehicles.'", "caveat": "Guerra and Millard-Ball (2017) later rejected the second-car explanation; the two measurements stand unreconciled in the literature.", "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-a2d6ea97cf37a835", "field": "body", "text": "the July 2008 Saturday extension had virtually no discernible effect across eight pollutants, and no sign that drivers switched to metro, bus or light rail", "statementKind": "quantitative", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-78b678356a3b5670" ], "supportNote": "The paper: 'Across eight major pollutants, the program expansion had virtually no discernible effect on pollution levels', and it turns to 'evidence from subway, bus, and light rail ridership, finding no evidence that the expansion was successful in getting drivers to switch to lower-emitting forms of transportation.'", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-f2e2e8bea7a58e40", "field": "body", "text": "reject the prevailing theory that its lack of success is due to perverse incentives for households to buy second cars", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-12e4c5d7271cd7b2", "src-344cf108280f6545" ], "supportNote": "Verbatim from the study's abstract, read in the authors' open preprint.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-2e5d5219cb84dd44", "field": "body", "text": "avoid the ban by shuffling weekly travel routines", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-12e4c5d7271cd7b2", "src-344cf108280f6545" ], "supportNote": "From the paper's highlights: 'Finds that households avoid ban by shuffling weekly travel routines.' The text adds: 'Shuffling travel days is less costly, more immediately available, and far simpler for most households than buying a second car.'", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } }, { "id": "clm-123a2c9c7699aada", "field": "body", "text": "Press reporting describes photo-enforcement cameras in Mexico City that sanction Hoy No Circula violations as well as speeding", "statementKind": "descriptive", "textMode": "verbatim-from-story-page", "mappingStatus": "mapped", "sourceRefs": [ "src-6d20cebdd4a72790" ], "supportNote": "adn40: 'Estos dispositivos no solo sancionan a quienes exceden la velocidad, también detectan conductores que circulan sin respetar las restricciones ambientales' — the devices sanction not only speeding but also detect drivers ignoring the environmental restrictions.", "caveat": null, "interpretation": { "added": false, "interpolation": false, "note": "The passport copies the published claim and its recorded source mapping without adding a conclusion." } } ], "sources": [ { "id": "src-ace305ebc8ebcd24", "title": "Davis, 'The Effect of Driving Restrictions on Air Quality in Mexico City', Journal of Political Economy 116(1), 2008, pp. 38-81", "url": "https://econpapers.repec.org/article/ucpjpolec/v_3a116_3ay_3a2008_3ai_3a1_3ap_3a38-81.htm", "publisher": { "name": null, "domain": "econpapers.repec.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-66cd2822e489894f", "clm-3918e7e8c63dfaa2", "clm-c05142d557d70a65", "clm-b6e0cd5194c879bb", "clm-9775dc12820fd6fd", "clm-6154072a52ebdd2b", "clm-0b5f70ac48d9cee9", "clm-31c3f86ab4d2e7aa" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "The load-bearing null result, abstract verbatim: 'In 1989, the government of Mexico City introduced a program, Hoy No Circula, that bans most drivers from using their vehicles one weekday per week on the basis of the last digit of the vehicle's license plate... Across pollutants and specifications there is no evidence that the restrictions have improved air quality. Evidence from additional sources indicates that the restrictions led to an increase in the total number of vehicles in circulation as well as a change in composition toward high-emissions vehicles.' Publisher page journals.uchicago.edu/doi/10.1086/529398; the author's own copy is at faculty.haas.berkeley.edu/ldavis/Davis%20JPE%202008.pdf but did not render from this desk, so the abstract was verified against this indexed mirror.", "exact": false }, "preservation": { "archiveUrl": "https://web.archive.org/web/20240428163441/https://econpapers.repec.org/article/ucpjpolec/v_3a116_3ay_3a2008_3ai_3a1_3ap_3a38-81.htm", "archivedAt": "2024-04-28", "contentHash": null, "status": "archive-linked" } }, { "id": "src-78b678356a3b5670", "title": "Davis, 'Saturday Driving Restrictions Fail to Improve Air Quality in Mexico City', Scientific Reports 7:41652, 2017", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC5289101/", "publisher": { "name": null, "domain": "pmc.ncbi.nlm.nih.gov", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-66cd2822e489894f", "clm-f8ae7d9a3609a2c4", "clm-3918e7e8c63dfaa2", "clm-0bae69017f650c62", "clm-9775dc12820fd6fd", "clm-a2d6ea97cf37a835" ], "temporal": { "publishedAt": "2017-02-02", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Dates the Saturday extension and grades it: 'Mexico City's driving restrictions were expanded to include Saturdays on July 5th, 2008.' and 'Overall, there is little evidence that the program expansion improved air quality.' Also the sentence this entry uses on enforcement: 'City police vigorously enforce the restrictions and vehicles violating the ban are easy to spot. Drivers caught violating the rules must pay a hefty fine and their vehicles are impounded for 48 hours.'", "exact": false }, "preservation": { "archiveUrl": "https://web.archive.org/web/20250302172243/https://pmc.ncbi.nlm.nih.gov/articles/PMC5289101/", "archivedAt": "2025-03-02", "contentHash": null, "status": "archive-linked" } }, { "id": "src-1aed7de45827ff4b", "title": "Gallego, Montero and Salas, 'The effect of transport policies on car use: Evidence from Latin American cities', Journal of Public Economics 107, 2013, pp. 47-62", "url": "https://econpapers.repec.org/RePEc:eee:pubeco:v:107:y:2013:i:c:p:47-62", "publisher": { "name": null, "domain": "econpapers.repec.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-45ffb8fffa657de4", "clm-b6e0cd5194c879bb", "clm-9775dc12820fd6fd", "clm-26c8718fff3952dd" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "Independently dates the programme to November 1989 ('the driving restriction program introduced in Mexico-City in November of 1989') and carries the study's method and direction in its abstract: hourly carbon monoxide records, and household responses 'not only ultimately unfortunate—more cars on the road and higher pollution levels—but also remarkably similar … on how fast households adjust their stock of vehicles, when they do.' The eleven-month figure sits in the paper's body behind Elsevier's paywall; the open working-paper version cited below carries it in its own abstract.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-7689b587dad366e5", "title": "Gallego, Montero and Salas, 'The Effect of Transport Policies on Car Use: Theory and Evidence from Latin American Cities', Documentos de Trabajo 407, Instituto de Economia, PUC Chile (2011) — open working-paper version", "url": "https://ideas.repec.org/p/ioe/doctra/407.html", "publisher": { "name": null, "domain": "ideas.repec.org", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-45ffb8fffa657de4", "clm-26c8718fff3952dd" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "The open working-paper version of the Journal of Public Economics article, cited for the figure the published abstract does not carry. Its abstract states verbatim: 'an expected short-run response followed by a rapid (before 11 months) increase in the stock of vehicles.'", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-344cf108280f6545", "title": "Guerra and Millard-Ball, 'Getting around a license-plate ban: behavioral responses to Mexico City's driving restriction', Transportation Research Part D 55, 2017", "url": "https://www.sciencedirect.com/science/article/abs/pii/S1361920917303498", "publisher": { "name": null, "domain": "sciencedirect.com", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-c02b4903279b2b8c", "clm-9775dc12820fd6fd", "clm-f2e2e8bea7a58e40", "clm-2e5d5219cb84dd44" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "The published record of the fourth peer-reviewed study. The publisher page blocks automated readers (403 on 2026-07-26 and again on 2026-08-27), so this entry cites the study from its abstract and from the author-hosted preprint below, not from a full read of the journal version. Publication date from Crossref (print issue August 2017, DOI 10.1016/j.trd.2017.06.027).", "exact": false }, "preservation": { "archiveUrl": "https://web.archive.org/web/20220729205240/http://www.sciencedirect.com/science/article/abs/pii/S1361920917303498", "archivedAt": "2022-07-29", "contentHash": null, "status": "archive-linked" } }, { "id": "src-12e4c5d7271cd7b2", "title": "Guerra and Millard-Ball, 'Getting around a license-plate ban' — author preprint, UCLA ITS (June 2017)", "url": "https://millardball.its.ucla.edu/wp-content/uploads/sites/22/2022/06/Guerra_Millard-Ball_Getting_around_a_license_plate_ban_June_2017_PREPRINT.pdf", "publisher": { "name": null, "domain": "millardball.its.ucla.edu", "classification": "not-classified" }, "sourceType": "pdf", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-c02b4903279b2b8c", "clm-b6e0cd5194c879bb", "clm-f2e2e8bea7a58e40", "clm-2e5d5219cb84dd44" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "The author-hosted open preprint of the Transportation Research Part D article, and the copy this entry was checked against. Abstract, verbatim: 'we reject the prevailing theory that its lack of success is due to perverse incentives for households to buy second cars. Instead, we highlight the range of other, less costly ways that people adjust behavior to avoid the restrictions.' The highlights add: 'Finds that households avoid ban by shuffling weekly travel routines.'", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-7d81a556f40673ac", "title": "SEDEMA, Ciudad de Mexico — Programa Hoy No Circula", "url": "https://sedema.cdmx.gob.mx/programas/programa/hoy-no-circula", "publisher": { "name": null, "domain": "sedema.cdmx.gob.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-f07d03e622030cbc", "clm-ee48b27635074471" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "The operator's own programme page and the correct citation for the current rules. It could not be read from this desk on either check (503 on 2026-07-26, connection failure on 2026-08-27); the rules this entry states rest on CAMe's description of the same programme and on El Universal's continuously updated rules page, both below.", "exact": false }, "preservation": { "archiveUrl": "https://web.archive.org/web/20260113044031/https://www.sedema.cdmx.gob.mx/programas/programa/hoy-no-circula", "archivedAt": "2026-01-13", "contentHash": null, "status": "archive-linked" } }, { "id": "src-debbf8eec8ff1891", "title": "Comision Ambiental de la Megalopolis — 'El Programa Hoy No Circula que aplica en la Zona Metropolitana del Valle de Mexico'", "url": "https://www.gob.mx/comisionambiental/prensa/el-programa-hoy-no-circula-que-aplica-en-la-zona-metropolitana-del-valle-de-mexico", "publisher": { "name": null, "domain": "gob.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-f07d03e622030cbc", "clm-ee48b27635074471" ], "temporal": { "publishedAt": "2025-04-01", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "CAMe's own description of the programme, comunicado 20/2025 of 1 April 2025, issued to knock down false rumours of extra restrictions: 'el programa Hoy No Circula que aplica en las 16 alcaldias de la Ciudad de Mexico y en 18 municipios conurbados del Estado de Mexico, no ha tenido cambios' ('the Hoy No Circula programme that applies in the 16 boroughs of Mexico City and 18 adjoining municipalities of the State of Mexico has not changed'). Carries the hologram rule verbatim: 'Los vehiculos con holograma 1 no circulan dos sabados del mes segun su terminacion, mientras que los vehiculos con holograma 2 no circulan ningun sabado del mes. Los vehiculos electricos e hibridos con holograma tipo Exento y aquellos con holograma 0 y 00 pueden circular todos los dias de la semana.' Direct fetch meets a challenge wall; read in full through a text-extraction proxy on 2026-08-27.", "exact": false }, "preservation": { "archiveUrl": "https://web.archive.org/web/20250401212427/https://www.gob.mx/comisionambiental/prensa/el-programa-hoy-no-circula-que-aplica-en-la-zona-metropolitana-del-valle-de-mexico", "archivedAt": "2025-04-01", "contentHash": null, "status": "archive-linked" } }, { "id": "src-ad142b48dbcb7470", "title": "Comision Ambiental de la Megalopolis — comunicado of 25 April 2026 maintaining the Fase I ozone contingency into the following Sunday", "url": "https://www.gob.mx/comisionambiental/prensa/se-mantiene-la-fase-i-de-contingencia-ambiental-atmosferica-por-ozono-en-la-zona-metropolitana-del-valle-de-mexico-424546", "publisher": { "name": null, "domain": "gob.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-a7148f006fd68da9", "clm-b110d027832a161a", "clm-a034516d71a831fc" ], "temporal": { "publishedAt": "2026-04-25", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "A live Fase I communique, read in full through a text-extraction proxy on 2026-08-27: CAMe 'informa que se mantiene la Fase I de contingencia ambiental atmosferica por ozono en la Zona Metropolitana del Valle de Mexico (ZMVM) y sus medidas para el dia de manana, domingo 26 de abril del 2026'. It shows who declares a contingency and that a declaration reaches even normally exempt cars: private vehicles with hologram 0 and 00, yellow sticker, plates ending 5 or 6, must stop from 5:00 to 22:00, while electric and hybrid vehicles and motorcycles stay exempt. Dated from the page's own text — it announces measures 'para el dia de manana, domingo 26 de abril del 2026', so it was issued on 25 April 2026; the operator's parallel communique 34/2026 of the same day carries the activation.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-988c68fa7ef99f12", "title": "El Horizonte — 'Activa CAME quinta contingencia ambiental por ozono en el ano' (25 April 2025)", "url": "https://www.elhorizonte.mx/nacional/activa-came-quinta-contingencia-ambiental-por-ozono-en-el-ano/3249729044", "publisher": { "name": null, "domain": "elhorizonte.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-a7148f006fd68da9", "clm-b110d027832a161a", "clm-7930dd5c009face8" ], "temporal": { "publishedAt": "2025-04-25", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Carries the 2025 count and its dates, verbatim: 'Esta es la quinta contingencia ambiental por ozono tras las del 26 de febrero, 18 de marzo, 1 de abril y 23 de abril, mientras que el 1 de enero se dio por mala calidad del aire y particulas suspendidas' ('This is the fifth ozone environmental contingency after those of 26 February, 18 March, 1 April and 23 April, while the one of 1 January was for bad air quality and suspended particles'). Also carries the trigger reading (159 ppb of ozone at the Ajusco Medio station at 15:00) and the threshold as reported to the public: 150 air-quality-index points.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-eae82745034bd9a6", "title": "El Universal — 'De Un Dia sin Auto a Hoy No Circula sabatino. Cronologia' (1 July 2008)", "url": "https://archivo.eluniversal.com.mx/notas/518895.html", "publisher": { "name": null, "domain": "archivo.eluniversal.com.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-4a03dd104b995183", "clm-c19d3297f5e262b6", "clm-f8ae7d9a3609a2c4", "clm-6154072a52ebdd2b", "clm-a86267d740091154", "clm-5bc4e82d9aa17579", "clm-da2d346b58597ddb" ], "temporal": { "publishedAt": "2008-07-01", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "A national newspaper's chronology of the programme, drawn from the then-DF environment secretariat. 1984: 'Arranca como iniciativa ciudadana \"Un dia Sin Auto\" … impulsada por la agrupacion ecologista \"Mejora tu Ciudad\"' (a voluntary citizens' initiative by an ecologist group). 1989: 'Aplica de manera oficial el programa Hoy No Circula (HNC) para la temporada invernal' (official, for the winter season). 1990: 'Extienden el programa … de manera permanente, ya no solo para la temporada invernal. Se establece el programa de Verificacion Vehicular' (made permanent, vehicle verification established). 2008: 'Lanzan para el 5 de julio el inicio de las restricciones' (Saturday restrictions launched for 5 July).", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-afdaf4d2258b3ff4", "title": "El Financiero — 'Hoy No Circula: origen, historia y por que se instauro este programa en la CDMX'", "url": "https://www.elfinanciero.com.mx/cdmx/2023/03/27/hoy-no-circula-origen-historia-y-por-que-se-instauro-este-programa-en-la-cdmx/", "publisher": { "name": null, "domain": "elfinanciero.com.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-66cd2822e489894f", "clm-6154072a52ebdd2b", "clm-5bc4e82d9aa17579" ], "temporal": { "publishedAt": "2023-03-27", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "Origin piece. The text served today carries the start date verbatim: 'El programa Hoy No Circula inicio el 20 de noviembre de 1989 ante una emergencia ambiental similar a la actual' ('began on 20 November 1989 during an environmental emergency similar to the current one'). The fuller history this entry once quoted from the same address — the 'Un Dia sin Auto' name and the 1990 accord — is no longer in the served text; those facts now rest on El Universal's chronology above.", "exact": false }, "preservation": { "archiveUrl": "https://web.archive.org/web/20260609030251/https://www.elfinanciero.com.mx/cdmx/2023/03/27/hoy-no-circula-origen-historia-y-por-que-se-instauro-este-programa-en-la-cdmx/", "archivedAt": "2026-06-09", "contentHash": null, "status": "archive-linked" } }, { "id": "src-3d24c58386c85927", "title": "El Universal — Hoy No Circula rules page (continuously updated reference)", "url": "https://www.eluniversal.com.mx/consultas/hoy-no-circula/", "publisher": { "name": null, "domain": "eluniversal.com.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "background", "claimRefs": [], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "A continuously updated rules-and-lookup page, so it publishes no date of its own. Checked on 2026-08-27, when it showed that day's restriction live: green sticker, plates ending 1 and 2, holograms 1 and 2, 5:00 to 22:00, applying in the 16 boroughs of Mexico City and 18 of the State of Mexico's 125 municipalities — the programme running unchanged in its thirty-seventh year.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-8d6241d5417f2cf6", "title": "El Universal — vehicle verification rules page (continuously updated reference)", "url": "https://www.eluniversal.com.mx/consultas/verificacion-vehicular/", "publisher": { "name": null, "domain": "eluniversal.com.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-c19d3297f5e262b6", "clm-ee48b27635074471" ], "temporal": { "publishedAt": null, "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "record-date-only" }, "locator": { "type": "descriptive-source-note", "value": "A continuously updated reference page, so it publishes no date of its own; checked on 2026-08-27. Carries the semester rhythm behind the holograms: each sticker colour has two verification windows a year (for example green, plates 1 and 2: April–May and October–November 2026), and hologram 0 is listed with 'vigencia semestral' — six-month validity.", "exact": false }, "preservation": { "archiveUrl": null, "archivedAt": null, "contentHash": null, "status": "not-captured" } }, { "id": "src-6d20cebdd4a72790", "title": "adn40 — photo-enforcement cameras that sanction Hoy No Circula in CDMX (4 September 2025)", "url": "https://www.adn40.mx/ciudad/2025-09-04/puntos-camaras-fotomultas-sancionan-hoy-no-circula-cdmx-como-aplica-hoy", "publisher": { "name": null, "domain": "adn40.mx", "classification": "not-classified" }, "sourceType": "web-page", "language": "und", "role": "claim-evidence", "claimRefs": [ "clm-123a2c9c7699aada" ], "temporal": { "publishedAt": "2025-09-04", "updatedAt": null, "sourceCheckedAt": null, "recordLastVerifiedAt": "2026-08-27", "dossierCreatedAt": "2026-08-27", "retrievedAt": null, "status": "publication-and-record-dates-recorded" }, "locator": { "type": "descriptive-source-note", "value": "The camera question, media-grade only: 'Estos dispositivos no solo sancionan a quienes exceden la velocidad, tambien detectan conductores que circulan sin respetar las restricciones ambientales' ('These devices do not only sanction those exceeding the speed limit, they also detect drivers circulating without respecting the environmental restrictions'), on a network described as more than 140 fixed cameras and radars plus mobile units, after CDMX restored economic photo-fines alongside the 2019 points-based fotocivicas. No official source confirming camera detection of Hoy No Circula was reachable, so this is not claimed in the snippet.", "exact": false }, "preservation": { "archiveUrl": "https://web.archive.org/web/20250906051652/https://www.adn40.mx/ciudad/2025-09-04/puntos-camaras-fotomultas-sancionan-hoy-no-circula-cdmx-como-aplica-hoy", "archivedAt": "2025-09-06", "contentHash": null, "status": "archive-linked" } } ], "coverage": { "claimsTotal": 28, "claimsMapped": 28, "sourcesTotal": 15, "sourcesUsedByClaims": 14, "sourcesWithPublicationDate": 7, "sourcesWithArchive": 7, "sourcesWithExactLocator": 0, "sourcesWithContentHash": 0 }, "limits": [ "Publisher names and source languages have not yet been classified; domains are recorded without guessing.", "Existing source notes are descriptive locators, not page- or paragraph-exact citations.", "A missing archive, publication date or content hash is shown as null rather than inferred.", "The project-level evidence grade ranks the strongest source in the entry; it is not a truth score for every claim." ] } } ] }