Permanent project revision

CTA Bus Tracker, Train Tracker & the Developer Feeds

Revision 2026-08-20-source-dates · effective 2026-07-26

Superseded. A later revision exists: 2026-08-20-source-dates-corrected →

unreviewed

Created the first structured Evidence Passport with 1 claim and 9 source dossiers.

sha256:a8a6805789c2026fc1b9b026733e1f56e77c0788f23351db3f2565b1b99cadce

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
9: source dossiers
1: publication dates recorded
1: 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-b62dd1cf01ab9e1a quantitative

A peer-reviewed study of route-level ridership across the staged 2006-2009 rollout found Bus Tracker did raise CTA bus ridership, though 'the average increase is modest'

Published field: impact · verbatim
Mapping: mapped · no interpretation or interpolation added by this passport
What the mapping says: The impact cites the study as Tang & Thakuriah, Transportation Research Part C, 2012.
Caveat: No claim-specific caveat recorded

Sources carrying this claim

Tang & Thakuriah — Ridership effects of a real-time bus information system: a case study in the City of Chicago (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 2026-07-26 · created 2026-08-20

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

sha256:a8a6805789c2026fc1b9b026733e1f56e77c0788f23351db3f2565b1b99cadce

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

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

Governance facts carried by the record

Operator: Chicago Transit Authority (CTA)
Actor types: utility
Funding model: public
Funding description: Not recorded
Cost: Not recorded
Ownership: Not recorded
Decision rights: Not recorded
Exit conditions: Not recorded

9 source dossiers

CTA Developer Center — open Chicago transit data (operator) transitchicago.com · background

Open original source ↗

Stable source ID: src-1f9a4f6718b97f74
Publisher: Name not classified · transitchicago.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: 2026-07-26
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
Lists the Bus Tracker API, Train Tracker API, Customer Alerts API, GTFS schedule data and the GTFS-Realtime feeds, each requiring a free registered developer key. Direct fetch from this environment returned 403; contents confirmed through the indexed CTA sub-pages, incl. the Train Tracker key application form. The Train Tracker developer guide (PDF, not renderable here) is the origin of the circulating default limit of 100,000 transactions per day — deliberately not asserted in the entry.
Descriptive only — not page/paragraph exact
Claims linked: Background source; no baseline claim points here

CTA Developer License Agreement and Terms of Use (operator) transitchicago.com · background

Open original source ↗

Stable source ID: src-d6103403e35129a7
Publisher: Name not classified · transitchicago.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: 2026-07-26
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
The licence, verified verbatim from a mirrored copy at openmobilitydata-data.s3-us-west-1.amazonaws.com/public/feeds/chicago-transit-authority/165/20150206/original/developers_license_agreement.htm: a 'limited, non-exclusive, non-assignable, non-transferable and revocable license'; data 'may not be used, in whole or in part, for any other purpose' than assisting riders or promoting public transportation; 'You will not sell, auction or barter any CTA Data separate from your application.' Attribution is explicitly optional. Data is supplied 'AS IS' with no representation as to accuracy or completeness.
Descriptive only — not page/paragraph exact
Claims linked: Background source; no baseline claim points here

Tang & Thakuriah — Ridership effects of a real-time bus information system: a case study in the City of Chicago (peer-reviewed) sciencedirect.com · 1 linked claim

Open original source ↗

Stable source ID: src-a310fc2668d0d9ab
Publisher: Name not classified · sciencedirect.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: 2026-07-26
Dossier created: 2026-08-20
Retrieved copy: No local capture recorded
Archive: Open archived copy ↗ · 2024-04-20
Content hash: No captured content hash
Locator: Open the recorded source note
Transportation Research Part C 22 (2012), 146-161. Uses the staged 2006-2009 rollout as a natural experiment on route-level monthly weekday ridership, January 2002 to December 2010. Abstract read at worldtransitresearch.info/research/4150/: 'the provision of Bus Tracker service does increase CTA bus ridership, although the average increase is modest.' The per-route trip figures circulating in secondary reports were not confirmable against the paper and are not used.
Descriptive only — not page/paragraph exact
Claims linked: clm-b62dd1cf01ab9e1a

Chicago Sun-Times — Chicago 'ghost buses' may be a thing of the past as CTA shares new data with transit apps (4 Aug 2025) chicago.suntimes.com · background

Open original source ↗

Stable source ID: src-9c4df3507eb41ebe
Publisher: Name not classified · chicago.suntimes.com
Type / language: web-page · language not classified
Published: 2025-08-04
Updated: Not recorded
Source last checked: No source-level check date
Record last verified: 2026-07-26
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
The consequence: the CTA began sharing cancelled runs on 1 May 2025 so they no longer appear as scheduled buses; Transit adopted it days later, Ventra, Google Maps and Apple Maps to follow. Carries the CTA's June 2025 delivery figures — 98.8% of scheduled buses, 88% of scheduled trains — and weekday ridership at about 69% of 2019.
Descriptive only — not page/paragraph exact
Claims linked: Background source; no baseline claim points here

Chi Hack Night — Ghost Buses project chihacknight.org · background

Open original source ↗

Stable source ID: src-d70829cb245b1010
Publisher: Name not classified · chihacknight.org
Type / language: web-page · language not classified
Published: Not recorded
Updated: Not recorded
Source last checked: No source-level check date
Record last verified: 2026-07-26
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
Civic-tech group formed spring 2022, project page November 2022. Scrapes the CTA Bus Tracker getvehicles feed every five minutes and compares it with the CTA's own GTFS schedule; collection began 20 May 2022. The clearest case in the atlas of an agency feed used to audit the agency.
Descriptive only — not page/paragraph exact
Claims linked: Background source; no baseline claim points here

Mansueto Institute for Urban Innovation (University of Chicago) & Chicago Tribune — CTA Stop Watch github.com · background

Open original source ↗

Stable source ID: src-de963b61597ab024
Publisher: Name not classified · github.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: 2026-07-26
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 analysis of over 100 million real-time bus locations from the Ghost Buses archive, June 2022 to July 2024: 'The CTA initially decreased scheduled service in early 2022 through 2023 to match the slower real-time performance and later increased it in early 2024.' Metrics include excess wait time and actual versus scheduled buses by community area.
Descriptive only — not page/paragraph exact
Claims linked: Background source; no baseline claim points here

Grid Chicago — The state of transit trackers in Chicago (2011) gridchicago.com · background

Open original source ↗

Stable source ID: src-e7ee9eea3fa7ebcd
Publisher: Name not classified · gridchicago.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: 2026-07-26
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
Chronology: pilot 5 August 2006 on route 20/Madison, thirteen routes by March 2008, last routes May 2009, Train Tracker 8 January 2011. Also records the sequence behind the API — a Chicago developer reverse-engineered the Bus Tracker feeds before the CTA formally released one. No launch date for the official API is given here or in any source found, so none is claimed.
Descriptive only — not page/paragraph exact
Claims linked: Background source; no baseline claim points here

US DOT ITS Knowledge Resources — CTA bus arrival prediction accuracy itskrs.its.dot.gov · background

Open original source ↗

Stable source ID: src-ab5788b0091a853f
Publisher: Name not classified · itskrs.its.dot.gov
Type / language: web-page · language not classified
Published: Not recorded
Updated: Not recorded
Source last checked: No source-level check date
Record last verified: 2026-07-26
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
Summarising the FTA-sponsored 'Traveler Information Systems and Wayfinding Technologies in Transit Systems' (2 May 2011): 'As a result, the Chicago Transit Authority (CTA) has a 92% accuracy rate for bus arrival prediction.' Self-reported by the CTA and relayed by a federal state-of-practice review, not an independent audit — recorded here rather than in the impact field. No independent evaluation of CTA prediction accuracy was found.
Descriptive only — not page/paragraph exact
Claims linked: Background source; no baseline claim points here

Mobility Database — Chicago Transit Authority GTFS schedule feed mobilitydatabase.org · background

Open original source ↗

Stable source ID: src-8a2fce3a88189f13
Publisher: Name not classified · mobilitydatabase.org
Type / language: web-page · language not classified
Published: Not recorded
Updated: 2026-08-07
Source last checked: No source-level check date
Record last verified: 2026-07-26
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
Currency check: feed listed Active, service window beginning 7 July 2026, quality report last updated 11 July 2026.
Descriptive only — not page/paragraph exact
Claims linked: Background source; no baseline claim points here

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.