1001 Smart Cities
🇺🇸 Chicago

Array of Things

🤖 AI-generated summary of the sources below · 🔎 Last verified · ◆ 9 sourced claims, none individually verified yet

This overview was generated with AI from the public sources listed below and checked against them before publication. It has not had a complete human fact-check — treat it as a starting point and follow the sources.

How this atlas is made · What “last verified” means · What “source-checked” means · The full record behind this page

✎ Corrected 27 Aug 2026 Record revised. What changed →

Chicago's 'fitness tracker for the city,' the Array of Things mounted modular sensor nodes on streetlight and traffic-signal poles from 2016, measuring air quality, noise and pedestrian traffic and publishing the readings as open data. The launch announced 500 nodes across the city by the end of 2018; about 130 were running four years later. A University of Chicago-Argonne partnership retired the original nodes in September 2021 after they outlived their planned lifespan, succeeded by the SAGE software-defined sensor network.

Completed 📅 2016–2021
Outcome🎯 Succeeded
Evidence🏛️ Official
what does this mean?The strongest source is the operator's or the city's own reporting — an official report, dataset or press release. It grades who did the looking — not how well the project went. All four grades →
Run byUniversity of Chicago & Argonne National Laboratory
Scale🏙️ City-wide

📊 Impact

The launch announced a total of 500 nodes across Chicago by the end of 2018. Four years in, in January 2021, the network was about 130 environmental sensors, and a planned expansion to 150 had been derailed by the pandemic; the original nodes were retired that September, after many had run four years, two beyond their planned lifespan.

🎓 Lesson

A sensor network's real size is the one that survives procurement and weather, not the one in the launch release: Chicago announced 500 nodes and ran about 130. What outlived the hardware was the software idea — the nodes went in 2021 and the work continued as SAGE, whose sensors can be given a new measurement by sending them a new program instead of putting up a new device. That is the part a later city can copy.

📡 Data & IoTAir qualityPublic spaceOpen dataSensors & IoT

Sources

↗ Array of Things (project)Official project website. Carries the retirement statement: the original nodes were retired in September 2021 after many had been in service for four years, two beyond their planned lifespans. Continuously maintained, so it carries no publication date.
↗ Argonne National Laboratory — Array of ThingsProject owner's description of the collaboration - Argonne, the University of Chicago, the Computation Institute and the School of the Art Institute - and of the 3.1 million dollar National Science Foundation grant behind the planned 500 nodes. It is the original project page and carries neither the retirement nor the successor network, and no publication date.
↗ University of Chicago News — launchPublished 29 August 2016Launch report, 29 August 2016: the first of an eventual 500 nodes, with a total of 500 to be installed across Chicago by the end of 2018.
↗ StateScoop (trade)Published 28 January 2021Status four years in, 28 January 2021: a network of 130 environmental sensors, with a planned expansion to 150 derailed by the pandemic, and an upgrade to software-defined nodes.
↗ GovTech (trade)Published 3 January 2018Industry publication reporting on the project.

📅 How old is the evidence?

Two clocks, kept apart: when this entry’s sources were published, and what has happened to its record in the atlas. Documented span: 2016–2021. 3 of 5 sources carry a publication date, from 29 August 2016 to 28 January 2021.

When the sources were published

  1. University of Chicago · researchUniversity of Chicago News — launch
  2. Government Technology (e.Republic) · pressGovTech (trade)
  3. StateScoop · pressStateScoop (trade)

Every source, with links ↑

What happened to this record

  1. Entered the record
  2. Sources last read
  3. Record revised

Every revision, permanent →

Show your work What this page rests on and what it can’t tell you · all 9 claims with their sources · the forensic record

Evidence Passport · public beta 9 addressable claims, 5 source dossiers, one permanent baseline. The passport is unreviewed — an AI-assisted structural migration, not a human or expert endorsement. Every revision keeps a permanent copy under revision history.

Inspect the claims, one by one — verbatim text, sources and caveats for all 9

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-dcb2542bbbecfd27 quantitative
the Array of Things mounted modular sensor nodes on streetlight and traffic-signal poles from 2016, measuring air quality, noise and pedestrian traffic and publishing the readings as open data
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Launch report of 29 August 2016: the first nodes were installed on city streets that week to measure air quality, climate, traffic and other urban features, in a University of Chicago, Argonne and City of Chicago partnership; the trade explainer covers the open-data publication.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. University of Chicago News — launch
  2. GovTech (trade)
Claim 2 clm-d474770f9ed3b09e quantitative
The launch announced 500 nodes across the city by the end of 2018; about 130 were running four years later
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Launch report: a total of 500 nodes will be installed across Chicago by the end of 2018. Four years on, the trade report describes a network of 130 environmental sensors placed around Chicago.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. University of Chicago News — launch
  2. StateScoop (trade)
Claim 3 clm-825d6e5f5e855118 quantitative
A University of Chicago-Argonne partnership retired the original nodes in September 2021 after they outlived their planned lifespan
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Project website: the original AoT nodes were retired in September 2021 after many had been in service for four years, two years beyond their planned lifespans.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Array of Things (project)
Claim 4 clm-1816d44e21092933 descriptive
succeeded by the SAGE software-defined sensor network
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
StateScoop, January 2021, describes the successor network and what makes it different: researchers can 'transmit a new program to the sensors rather than having to install new hardware'.
Caveat
Argonne's own project page still describes the original deployment and does not mention the successor.

Sources carrying this claim

  1. StateScoop (trade)
Claim 5 clm-e605b46f570bcc62 quantitative
The launch announced a total of 500 nodes across Chicago by the end of 2018
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Launch report of 29 August 2016.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. University of Chicago News — launch
Claim 6 clm-a51375ded8fef728 quantitative
Four years in, in January 2021, the network was about 130 environmental sensors, and a planned expansion to 150 had been derailed by the pandemic
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Trade report of 28 January 2021: a network of 130 environmental sensors placed around Chicago over the last four years, with a plan to expand to 150 the previous year derailed by the COVID-19 pandemic.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. StateScoop (trade)
Claim 7 clm-4d67e4a6f178515c descriptive
the original nodes were retired that September, after many had run four years, two beyond their planned lifespan
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Project website's retirement statement.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Array of Things (project)
Claim 8 clm-28486444f9b73b63 quantitative
Chicago announced 500 nodes and ran about 130
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Launch report and the four-year status report side by side.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. University of Chicago News — launch
  2. StateScoop (trade)
Claim 9 clm-0a7e0752e7b7fac8 descriptive
SAGE, whose sensors can be given a new measurement by sending them a new program instead of putting up a new device
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Trade report: the new nodes use software-defined networking, allowing the team to transmit a new program to the sensors rather than having to put up a new device to take a new type of measurement.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. StateScoop (trade)
Forensic record — source dossiers, gaps, hashes and the exact revision this page renders

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 2026-08-27-correction-run effective 2026-08-26 · created 2026-08-27

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

sha256:559f0a9888e3167efcdad4636b2770bc29b65549eb819630c271516b21ab53fc
Revision history → Permanent version link → Machine-readable record → Evidence Constitution →
9
of 9 claims mapped
5
source dossiers
3
publication dates recorded
0
archives linked
0
exact locators
0
content captures hashed

Governance facts carried by the record

Operator
University of Chicago & Argonne National Laboratory
Actor types
research
Funding model
Not recorded
Funding description
Not recorded
Cost
Not recorded
Ownership
Not recorded
Decision rights
Not recorded
Exit conditions
Not recorded

5 source dossiers

Array of Things (project) arrayofthings.github.io · 2 linked claims

Open original source ↗

Stable source ID
src-f01c8b65458dfdd4
Publisher
Name not classified · arrayofthings.github.io
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-26
Dossier created
2026-08-27
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Official project website. Carries the retirement statement: the original nodes were retired in September 2021 after many had been in service for four years, two beyond their planned lifespans. Continuously maintained, so it carries no publication date.

Descriptive only — not page/paragraph exact
Claims linked
Argonne National Laboratory — Array of Things anl.gov · background

Open original source ↗

Stable source ID
src-ab26ab5c1ef95ea9
Publisher
Name not classified · anl.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
2026-08-26
Dossier created
2026-08-27
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Project owner's description of the collaboration - Argonne, the University of Chicago, the Computation Institute and the School of the Art Institute - and of the 3.1 million dollar National Science Foundation grant behind the planned 500 nodes. It is the original project page and carries neither the retirement nor the successor network, and no publication date.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
University of Chicago News — launch news.uchicago.edu · 4 linked claims

Open original source ↗

Stable source ID
src-9662fcfef8142fc6
Publisher
Name not classified · news.uchicago.edu
Type / language
web-page · language not classified
Published
2016-08-29
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-26
Dossier created
2026-08-27
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Launch report, 29 August 2016: the first of an eventual 500 nodes, with a total of 500 to be installed across Chicago by the end of 2018.

Descriptive only — not page/paragraph exact
Claims linked
StateScoop (trade) statescoop.com · 5 linked claims

Open original source ↗

Stable source ID
src-e2cc310e81693bfd
Publisher
Name not classified · statescoop.com
Type / language
web-page · language not classified
Published
2021-01-28
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-26
Dossier created
2026-08-27
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Status four years in, 28 January 2021: a network of 130 environmental sensors, with a planned expansion to 150 derailed by the pandemic, and an upgrade to software-defined nodes.

Descriptive only — not page/paragraph exact
Claims linked
GovTech (trade) govtech.com · 1 linked claim

Open original source ↗

Stable source ID
src-c1ba96d832dc2c75
Publisher
Name not classified · govtech.com
Type / language
web-page · language not classified
Published
2018-01-03
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-26
Dossier created
2026-08-27
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
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.

Continue exploring

Compare this project

🇪🇸 SmartSantander · Santander Two pioneering open sensor testbeds, both retired: Santander's EU pilot came first (2010–13); Chicago's 100+ pole nodes ran 2016–21. 🇳🇵 Kathmandu Metropolitan Air Quality Monitoring Dashboard · Kathmandu Open-data air sensing, a decade apart: Chicago's pole nodes published readings 2016–21; Kathmandu launched its own city network in 2025. 🇫🇷 Plan Vélo Digital Infrastructure Mesh · Paris Kindred open-data street sensors: Chicago's poles measured air and foot traffic 2016–21; Paris's bike counters publish hourly.

Explore the wider context

📟 A Reading Is Not a Decision🌫️ Air quality guide🏙️ Chicago city profile📡 Data & IoT projects📖 Air quality index (AQI)📖 Low-emission zone📖 Open data
📎 Cite this project

1001 Smart Cities (2026). “Array of Things” — Chicago, United States. The Smart City Atlas. https://1001smartcities.org/projects/chicago-array-of-things/ (last verified 2026-08-26). Data: CC BY 4.0.

The underlying data is free to reuse with attribution — see the open data page.

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