Resilience Scanner

Array of Things Urban Environmental Sensing Network

Solution Overview

The Array of Things represents an urban sensing infrastructure deployed across Chicago to collect real-time environmental and operational data through a network of interactive, modular sensor boxes mounted on streetlight poles.[11][8] This federally funded initiative was developed through a partnership between the City of Chicago, University of Chicago, and Argonne National Laboratory to enable data-driven decision-making for urban challenges.[4] The datasets gathered make Chicago a truly 'smart city,' allowing the City to operate more efficiently and realize cost savings by anticipating and proactively addressing challenges such as urban flooding and traffic safety.[11][1]

Technical Components

The sensor nodes consist of protective shields containing up to 15 sensors, a computer, two cameras, a microphone, and a cooling fan.[6] These instruments measure temperature, barometric pressure, light, vibration, carbon monoxide, nitrogen dioxide, sulfur dioxide, ozone, ambient sound intensity, pedestrian and vehicle traffic, and surface temperature.[1][8][13] The nodes include cameras and a microphone, along with sensors for humidity, vibration, magnetic fields, temperature, air pollution, and barometric pressure.[9] Each node was equipped with an Nvidia graphics processing unit to perform computations on images out in the field and sent only processed data along to the network—a form of edge computing.[9] The nodes utilize an Argonne-developed technology platform called Waggle, which allows for powerful and secure remote processing of measurements before transmission of data to a central server.[3] Creek images are collected using a downward-facing camera that captures a 96-dpi image every second.[7] With continued development, the system may soon be able to collect data on flooding and standing water, precipitation, and wind.[6] Additional capabilities were developed using the platform, such as methods for interpreting weather and image data to detect standing water and urban flooding.[1][3]

Implementation Details

The National Science Foundation awarded a $3.1 million grant in fall 2015 to support the development of this urban sensing instrument.[1][3][6] Charlie Catlett's initiative received $12 million in National Science Foundation funding over 10 years.[9] Additional funding was provided by the University of Chicago Innovation Fund, Argonne National Laboratory (which contributed more than $1 million in internal research funding), and the John D. and Catherine T. MacArthur Foundation.[1][3][6] The project was first publicly announced in June 2014.[6] The NSF grant funded the development and installation of 500 sensor nodes, with 50 nodes planned for installation in early 2016, 200 by the end of 2016, and 500 by the end of 2017.[1][3] Between 2016 and 2019, the team attached 140 nodes to Chicago streetlights.[9] In August 2016, the team installed the first current nodes on two light posts on Chicago's near southwest side and activated those nodes in October 2016.[6] The project launched in 2016, with sensor boxes mounted on light posts collecting real-time data on Chicago's environmental surroundings and urban activity.[6][12] To date, more than 140 sensor nodes have been deployed throughout the City of Chicago in a variety of neighborhoods to assess micro-environmental conditions such as weather, air quality, noise levels, and both human and vehicle traffic flow.[5] By 2018, the goal was to place 500 nodes on traffic poles throughout Chicago, with each node comprising 28 sensors, 2 cameras and a microphone.[4] The original nodes were retired in September 2021 after many had been in service for 4 years, two years beyond their planned lifespans.[13] SAGE test units replaced a number of original nodes in late 2021, with many more planned to be replaced in 2022 as the new platform underwent extensive testing and evaluation.[13] By the end of 2025, the team planned to install 50 of the $10,000 nodes in Chicago, replacing the earlier-generation nodes.[9]

The project was led by researchers from the Urban Center for Computation and Data at the Computation Institute, a joint initiative of Argonne National Laboratory and the University of Chicago under the direction of Argonne computer scientist Charlie Catlett.[6][10] The multidisciplinary team included designers, engineers and scientists at the Computation Institute, the School of the Art Institute of Chicago, Northern Illinois University and the University of Illinois at Urbana-Champaign.[1][10] Efforts to develop the Waggle platform—the software and hardware that powers the project—were led by Argonne Institute of Science and Engineering Co-Director Pete Beckman, together with Rajesh Sankaran and Catlett.[6][10] The initiative was executed in partnership with the City of Chicago, which installed nodes onto light posts across the city via its Department of Transportation.[6] The City's Department of Innovation and Technology served as the lead agency on the project and managed Chicago's data portal, which housed the data for the public.[6] Civic organization Smart Chicago Collaborative managed community engagement and public outreach.[6] Other partners included a collective of scientists from twelve universities worldwide, as well as technical advice and support from industry partners such as Microsoft, Cisco, and Motorola Solutions.[6] In a participatory process, the team at Argonne and local universities worked with everyday Chicagoans and city departments to decide where to place the sensors.[9] All citizens could submit proposals for where a node should be placed, whether in their neighborhood or elsewhere.[4] In August 2016, the project released the final version of the project's governance and privacy policies, as well as responses to public feedback and the Civic Engagement Report.[6][12] An oversight committee, comprised of academic researchers, city officials and cybersecurity experts, regularly reviewed the project and additional technologies that may be developed and added to it in the future, assisted by an independent security and privacy review team and an external scientific advisory committee.[3]

In 2021, the team partnered with multiple Chicago community areas, the City of Chicago, Microsoft Research Urban Innovation team, and JCDecaux on project Eclipse to design an experimental air pollution monitoring network with sensors on 115 Chicago bus shelters.[13] The team partnered with Microsoft Research to install 115 low-cost solar-powered air quality sensors on bus shelters across the city.[9]

Benefits and Impacts

The system provides real-time, location-based data about the city's environment, infrastructure and activity to researchers and the public.[8] All information measured is publicly available for free through the City of Chicago Data Portal and other open data platforms.[1] Because the data is published openly and without charge, it supports the equitable development of innovative applications, such as a mobile application that allows residents to track their exposure to certain air contaminants, or to navigate through the city based on avoiding urban heat islands, poor air quality, or excessive noise and congestion.[11][13] For local government, data generated by the sensors helps make both short-term operations and long-term planning more efficient and effectively realizes cost savings by anticipating floods, traffic safety incidents, and other challenges.[6] The nodes have been used to assess the safety of at-grade rail crossings, monitor pedestrian crosswalk usage, and detect flooding along the Chicago River.[9] The nodes allow the city to track vehicle and pedestrian collisions to understand which intersections or traffic flows lead to pedestrian deaths and make urban planning changes accordingly.[4]

Chicago's current monitoring of temperature data was based on just three sensors across the city, but with temperature data becoming available at hyper-local levels, the city could vastly improve its understanding of micro-level weather patterns and better estimate where to apply salt before snow storms.[6] Climate researchers have dramatically higher resolution data than currently provided by existing weather stations to study urban microclimates, with benefits for hyper-local weather forecasting and energy efficiency.[3] The nodes can be used to detect standing water in Chicago's West and South sides during rainstorms, helping city employees identify bottlenecks in the city's sewer system.[4] Chicago has one of the worst incidences of asthma mortality in the country; the nodes help monitor air pollutant levels across the city and take appropriate measures where necessary.[4] The resulting data from the bus shelter sensors showed pollution hot spots near industrial corridors on Chicago's South and West Sides in unprecedentedly high resolution.[9] Kathleen Cagney, who directs the Institute for Social Research at the University of Michigan, used environmental data from the sensors for a study on public health, finding higher asthma rates in places where sensors detected more air pollution.[9] Nodes support advanced capabilities such as measuring sound levels on busy streets and around public transportation, or assessing air quality in neighborhoods near industrial facilities.[3]

Climate Adaptation Relevance

This urban sensing infrastructure directly addresses climate adaptation challenges by enabling the city to anticipate and proactively address urban flooding through real-time detection of standing water and identification of sewer system bottlenecks.[11][4] The system measures factors that impact livability such as climate, air quality and noise, serving as a figurative 'fitness tracker' for the city.[11][12] The initiative enables scientific investigation of solutions to urban challenges ranging from air quality to urban flooding through comprehensive environmental monitoring.[1][3]

Business Analysis

The project was funded primarily by the U.S. National Science Foundation under grant NSF 1532133, with a $3.1 million initial award and $12 million total over 10 years.[5][9][1] Additional funding was provided by the University of Chicago Innovation Fund, Argonne National Laboratory (contributing more than $1 million in internal research funding), and the John D. and Catherine T. MacArthur Foundation.[1][3][6] The newer generation nodes cost approximately $10,000 per unit.[9] The project was part of the White House Smart Cities Initiative.[10] Working with the City of Chicago's Department of Transportation and Department of Innovation and Technology, the initiative boosted local research, development, prototyping and the demonstration of new technologies and services.[1] The project represented the first at-scale research infrastructure deployment enabling researchers to study an urban environment.[10] Serious questions existed around the sustainability of non-profit funding if the city wanted to expand the project, as the city budget would struggle to take on yet another line item.[4] The immeasurable value of increased civil engagement from Chicago's citizens, with all citizens able to submit proposals for where a node should be placed, represented an additional benefit beyond direct cost savings.[4]

Sources