Permanent project revision

Ultra Low Emission Zone (ULEZ)

Revision 2026-08-20-source-dates · effective 2026-07-17

Current revision. This is the snapshot used by the live entity page.

unreviewed

Created the first structured Evidence Passport with 1 claim and 6 source dossiers.

sha256:54f19375627ebf0d37d7db33647e449761627a7e9e35c99113c5750a8350ff4b

All revisions → Current entity page →

Change set

add /evidencePassport — Added claim-level evidence mapping and source dossiers.
add /revisionHistory — Established a permanent, hash-addressed baseline revision.

1: of 1 claims mapped
6: source dossiers
3: publication dates recorded
0: archives linked
0: exact locators
0: content captures hashed

Claims, one by one

The text below is copied verbatim from the published record. Each claim names the source dossiers that carry it; caveats stay attached to the claim they qualify.

Claim 1 clm-25dbbb66a2336acc quantitative

An independent peer-reviewed study (Elliott et al., npj Clean Air, 2025) measured a more modest ~19.6% NO2 cut at central-London traffic sites after the 2019 zone, and no detectable effect from the 2023 outer expansion

Published field: impact · verbatim
Mapping: mapped · no interpretation or interpolation added by this passport
What the mapping says: No support note recorded
Caveat: TfL's own One Year Report estimates larger effects — roadside NO2 27% lower across London in 2024 and 54% lower in central London.

Sources carrying this claim

Elliott et al. 2025, npj Clean Air (peer-reviewed)

Source dossiers and revision state

This layer records what is known about each source, what is still missing, and the exact snapshot this page is rendering. A missing date, archive or hash stays visible as missing.

unreviewed Revision 2026-08-20-source-dates effective 2026-07-17 · created 2026-08-20

Awaiting operator and domain-expert review; publication of this revision implies neither.

sha256:54f19375627ebf0d37d7db33647e449761627a7e9e35c99113c5750a8350ff4b

Revision history → Permanent version link → Machine-readable record → Evidence Constitution →

1: of 1 claims mapped
6: source dossiers
3: publication dates recorded
0: archives linked
0: exact locators
0: content captures hashed

Governance facts carried by the record

Operator: Transport for London (TfL)
Actor types: utility
Funding model: public
Funding description: Not recorded
Cost: Not recorded
Ownership: Not recorded
Decision rights: Not recorded
Exit conditions: Not recorded

6 source dossiers

Transport for London (authority) tfl.gov.uk · background

Open original source ↗

Stable source ID: src-97ebd5d47555d6c4
Publisher: Name not classified · tfl.gov.uk
Type / language: web-page · language not classified
Published: Not recorded
Updated: Not recorded
Source last checked: No source-level check date
Record last verified: 2026-07-17
Dossier created: 2026-08-20
Retrieved copy: No local capture recorded
Archive: No archived copy linked
Content hash: No captured content hash
Locator: Open the recorded source note
Official page by the city or public authority behind the project.
Descriptive only — not page/paragraph exact
Claims linked: Background source; no baseline claim points here

Londonist (press) londonist.com · background

Open original source ↗

Stable source ID: src-e88e34ca2954c7d0
Publisher: Name not classified · londonist.com
Type / language: web-page · language not classified
Published: Not recorded
Updated: Not recorded
Source last checked: No source-level check date
Record last verified: 2026-07-17
Dossier created: 2026-08-20
Retrieved copy: No local capture recorded
Archive: No archived copy linked
Content hash: No captured content hash
Locator: Open the recorded source note
News coverage of the August 2023 London-wide expansion.
Descriptive only — not page/paragraph exact
Claims linked: Background source; no baseline claim points here

Centre for Cities (trade) centreforcities.org · background

Open original source ↗

Stable source ID: src-db296f845b951877
Publisher: Name not classified · centreforcities.org
Type / language: web-page · language not classified
Published: 2022-12-01
Updated: 2022-12-06
Source last checked: No source-level check date
Record last verified: 2026-07-17
Dossier created: 2026-08-20
Retrieved copy: No local capture recorded
Archive: No archived copy linked
Content hash: No captured content hash
Locator: Open the recorded source note
Industry publication reporting on the project.
Descriptive only — not page/paragraph exact
Claims linked: Background source; no baseline claim points here

University of Birmingham (research) birmingham.ac.uk · background

Open original source ↗

Stable source ID: src-53095389fb730e09
Publisher: Name not classified · birmingham.ac.uk
Type / language: web-page · language not classified
Published: 2025-10-22
Updated: Not recorded
Source last checked: No source-level check date
Record last verified: 2026-07-17
Dossier created: 2026-08-20
Retrieved copy: No local capture recorded
Archive: No archived copy linked
Content hash: No captured content hash
Locator: Open the recorded source note
Independent study (npj Clean Air, Oct 2025): the 2019 zone cut roadside NO2 quickly; high prior compliance left little gain from the 2023 expansion.
Descriptive only — not page/paragraph exact
Claims linked: Background source; no baseline claim points here

TfL — ULEZ One Year Report (authority) content.tfl.gov.uk · background

Open original source ↗

Stable source ID: src-f761866c1d1f34a3
Publisher: Name not classified · content.tfl.gov.uk
Type / language: pdf · language not classified
Published: Not recorded
Updated: Not recorded
Source last checked: No source-level check date
Record last verified: 2026-07-17
Dossier created: 2026-08-20
Retrieved copy: No local capture recorded
Archive: No archived copy linked
Content hash: No captured content hash
Locator: Open the recorded source note
Official evaluation of the London-wide zone, published March 2025 — source of the impact figures.
Descriptive only — not page/paragraph exact
Claims linked: Background source; no baseline claim points here

Elliott et al. 2025, npj Clean Air (peer-reviewed) nature.com · 1 linked claim

Open original source ↗

Stable source ID: src-22d3b2b43309a95b
Publisher: Name not classified · nature.com
Type / language: web-page · language not classified
Published: 2025-10-22
Updated: Not recorded
Source last checked: No source-level check date
Record last verified: 2026-07-17
Dossier created: 2026-08-20
Retrieved copy: No local capture recorded
Archive: No archived copy linked
Content hash: No captured content hash
Locator: Open the recorded source note
Independent causal study: ~19.6% NO2 cut at central-London traffic sites after the 2019 ULEZ; no detectable effect from the 2023 outer expansion.
Descriptive only — not page/paragraph exact
Claims linked: clm-25dbbb66a2336acc

Known limits of this passport

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.