1001 Smart Cities

Permanent project revision

Surtrac AI Traffic Signals

Revision 2026-10-14-baseline · effective 2026-10-14

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

unreviewed

Created the first structured Evidence Passport with 14 claims and 7 source dossiers.

sha256:a4e00411d662661a6d3c0605be74aa8acc7a6c7a1e88a87e32726b94f9fed270
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.
14
of 14 claims mapped
7
source dossiers
5
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-73fded42b67a6641 descriptive
Born at Carnegie Mellon
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
Spectrum describes Surtrac as developed by CMU robotics professor Stephen Smith, whose startup commercialises it.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. IEEE Spectrum (press)
Claim 2 clm-dfdfb88da4f6e3fb descriptive
decentralised AI traffic lights that negotiate with neighbours in real time, each optimising its own intersection
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
Spectrum: the system is decentralised, each signal makes its own timing decisions and sends data to downstream intersections so they can plan ahead.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. IEEE Spectrum (press)
Claim 3 clm-085e923fc8a22506 quantitative
In CMU's East Liberty pilot they cut travel times ~25% and idling over 40%
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
Spectrum reports pilot tests in Pittsburgh that reduced travel time by 25 percent and idling time by over 40 percent.
Caveat
These are the research team's own drive-run figures.

Sources carrying this claim

  1. IEEE Spectrum (press)
Claim 4 clm-d4f947735e23b1e5 quantitative
By 2016 the network spanned 50 Pittsburgh intersections
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
Spectrum (October 2016) says the network now spans 50 intersections; the CMU page describes the 2020 upgrade at all 50.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. IEEE Spectrum (press)
  2. CMU Metro21 – Surtrac 2.0 (research authority)
Claim 5 clm-ca080648f71213b5 quantitative
Rapid Flow Technologies, the CMU spinout selling Surtrac, was acquired by Miovision in 2022
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
BetaKit (12 October 2022) reports that Miovision has acquired Pittsburgh tech company Rapid Flow Technologies, which provides Surtrac.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. BetaKit — Miovision acquires Rapid Flow (press)
Claim 6 clm-b74c6dfb02f5a2b2 quantitative
CMU-reported East Liberty pilot (9 intersections, 2012)
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
Spectrum: Smith's team started with nine intersections in East Liberty in 2012.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. IEEE Spectrum (press)
Claim 7 clm-3446877e99b51641 quantitative
~25% shorter travel times, over 40% less idling and ~21% lower emissions — research-team figures, not independently audited
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
Spectrum gives 25% travel time, over 40% idling and a researcher estimate of 21% fewer emissions; all come from the developers.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. IEEE Spectrum (press)
Claim 8 clm-10fb27203586c229 quantitative
An outside peer-reviewed study of a 23-intersection corridor, with the system switched on and off, found significant reductions in stops and better travel-time reliability
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The abstract describes a 23-intersection Pittsburgh corridor, data collected with the system active and inactive, significant improvements in the number of stops and improved reliability over six months of probe data.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Khattak, Magalotti & Fontaine, Journal of Intelligent Transportation Systems (peer-reviewed)
Claim 9 clm-d8fb84f42f746af4 descriptive
but travel-time gains only in the westbound peaks and a significant midday speed drop on one street
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The abstract: on Baum and Centre travel times improved during the AM and PM peak in the westbound direction; a statistically significant decrease in speed was observed during the midday period on Centre westbound.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Khattak, Magalotti & Fontaine, Journal of Intelligent Transportation Systems (peer-reviewed)
Claim 10 clm-e398ca1ee52c7099 quantitative
In 2022 the city planned adaptive signals at close to 150 intersections along eight 'Smart Spines' corridors
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
Route Fifty (May 2022) reports the plan to revamp close to 150 city intersections in eight 'Smart Spines' corridors.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Route Fifty — Smart Spines (press)
Claim 11 clm-c3e5ef8d4718a6f9 descriptive
no source since says how many run today
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The newest deployment count in the sources is the CMU page's 2020 update on all 50 intersections; the 2022 report gives only the plan.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. CMU Metro21 – Surtrac 2.0 (research authority)
  2. Route Fifty — Smart Spines (press)
Claim 12 clm-08ff1f88920c7dc0 descriptive
Check a developer's headline against a switched-off comparison
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The study notes that the developers' evaluation reported large reductions without statistical evaluation, and itself compared the system active and inactive.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Khattak, Magalotti & Fontaine, Journal of Intelligent Transportation Systems (peer-reviewed)
Claim 13 clm-e7a9f7a5c55e9dcd quantitative
Surtrac's ~25% came from before-and-after drive runs
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
Spectrum attributes the 25% figure to the developers' pilot tests in Pittsburgh.
Caveat
The method (timed drive-through runs before and after) is described in the developers' own papers, not in this article.

Sources carrying this claim

  1. IEEE Spectrum (press)
Claim 14 clm-4e5f325b1af6bb0b descriptive
while the independent on/off study found the gains concentrated in fewer stops and steadier trips rather than uniformly shorter journeys
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this file
What the mapping says
The abstract reports significant gains in stops and reliability, travel-time gains only in some directions and periods.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Khattak, Magalotti & Fontaine, Journal of Intelligent Transportation Systems (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 2026-10-14-baseline effective 2026-10-14 · created 2026-10-14

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

sha256:a4e00411d662661a6d3c0605be74aa8acc7a6c7a1e88a87e32726b94f9fed270
Revision history → Permanent version link → Machine-readable record → Evidence Constitution →
14
of 14 claims mapped
7
source dossiers
5
publication dates recorded
0
archives linked
0
exact locators
0
content captures hashed

Governance facts carried by the record

Operator
Rapid Flow Technologies / Miovision (Carnegie Mellon spinout)
Actor types
private
Funding model
public
Funding description
Not recorded
Cost
$30M plan (city and PennDOT, 2017; city share $7M)
Ownership
Not recorded
Decision rights
Not recorded
Exit conditions
Not recorded

7 source dossiers

Miovision — Surtrac adaptive product page (vendor) rapidflowtech.com · background

Open original source ↗

Stable source ID
src-ebfe7a5c4800e351
Publisher
Name not classified · rapidflowtech.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
2026-10-14
Dossier created
2026-10-14
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The former Rapid Flow address now opens Miovision's Surtrac adaptive page, which credits the initial Pittsburgh deployment with 25% faster trips, over 40% less waiting and 20% fewer emissions.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
IEEE Spectrum (press) spectrum.ieee.org · 7 linked claims

Open original source ↗

Stable source ID
src-4afbdbb867e69105
Publisher
Name not classified · spectrum.ieee.org
Type / language
web-page · language not classified
Published
2016-10-17
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-14
Dossier created
2026-10-14
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

2016 coverage of the CMU pilot: 25% shorter travel time, over 40% less idling, an estimated 21% fewer emissions, nine intersections in 2012 grown to 50.

Descriptive only — not page/paragraph exact
Claims linked
CMU Metro21 – Surtrac 2.0 (research authority) cmu.edu · 2 linked claims

Open original source ↗

Stable source ID
src-5cf56624436da1f1
Publisher
Name not classified · cmu.edu
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-14
Dossier created
2026-10-14
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Carnegie Mellon project page on the Surtrac 2.0 upgrade done at the City's request; its April 2020 update describes reinstalling the system at all 50 intersections.

Descriptive only — not page/paragraph exact
Claims linked
Khattak, Magalotti & Fontaine, Journal of Intelligent Transportation Systems (peer-reviewed) tandfonline.com · 4 linked claims

Open original source ↗

Stable source ID
src-12623711e5c7d72d
Publisher
Name not classified · tandfonline.com
Type / language
web-page · language not classified
Published
2019-05-20
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-14
Dossier created
2026-10-14
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

University of Pittsburgh and Virginia researchers evaluated Surtrac on a 23-intersection corridor with the system active and inactive, using GPS floating-car runs and six months of INRIX probe data.

Descriptive only — not page/paragraph exact
Claims linked
Route Fifty — Smart Spines (press) route-fifty.com · 2 linked claims

Open original source ↗

Stable source ID
src-357919894abc8c29
Publisher
Name not classified · route-fifty.com
Type / language
web-page · language not classified
Published
2022-05-10
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-14
Dossier created
2026-10-14
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Reports the city's plan to bring Surtrac adaptive signalling to close to 150 intersections along eight 'Smart Spines' corridors.

Descriptive only — not page/paragraph exact
Claims linked
NEXTpittsburgh — $30 million smart-signal plan (press) nextpittsburgh.com · background

Open original source ↗

Stable source ID
src-d3140bfe791a275a
Publisher
Name not classified · nextpittsburgh.com
Type / language
web-page · language not classified
Published
2017-08-28
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-14
Dossier created
2026-10-14
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The city and PennDOT plan a $30 million adaptive signal system, mostly federal and state money, with a $7 million city share and a three-year build-out.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
BetaKit — Miovision acquires Rapid Flow (press) betakit.com · 1 linked claim

Open original source ↗

Stable source ID
src-b3714c5c4639e7eb
Publisher
Name not classified · betakit.com
Type / language
web-page · language not classified
Published
2022-10-12
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-10-14
Dossier created
2026-10-14
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Reports that Miovision has acquired Rapid Flow Technologies, maker of Surtrac, for an undisclosed amount.

Descriptive only — not page/paragraph exact
Claims linked
Known limits of this file
  • 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.