Carnegie Mellon University

airport display

Metro21 display has arrived at the Pittsburgh International Airport

The Metro21 display, featuring Surtrac, is located in Concourse A near gate A10! This display showcases the partnership between Carnegie Mellon and the city of Pittsburgh by highlighting the benefits of smart traffic lights.

In 2009, Henry Hillman reached out to Carnegie Mellon University looking for a technology that could enable traffic to move more smoothly. Hillman hoped that this technology could be spun out of Carnegie Mellon into a start-up that could create more jobs in the city. This sparked the creation of Traffic21, a multidisciplinary research institute with the goal to design, test, deploy and evaluate information and communications-technology-based solutions to address transportation problems.

In 2014, Metro21 formed from Traffic21 with the goal of developing 21st century solutions to the challenges facing metropolitan regions. Metro21 is a university-wide institute with a unique interdisciplinary platform that builds strong partnerships with government, private and non-profit sectors to addressing real-world issues through research, development and deployment. Since 2014, Metro21 has funded over 50 projects relating to paving the way for Smart Cities, including Surtrac.

Surtrac spun out of Carnegie Mellon in 2015. Stephen Smith, a research professor in CMU's Robotics Institute, leads Surtrac. His group researches work related to multi-agent decision-making and developed an AI technique called “online collaborative planning.”

Smith views Surtrac as “a piece of a mobility puzzle – key to quality life, equality of opportunity, and economic benefit.” The team focuses on problems where no one agent is in charge and decisions happen as a collaborative activity. It was a very natural application to apply to traffic lights."

The Surtrac software allows the signals to "talk to each other." Each signal makes its own decisions on timing by sensing approaching traffic streams and generating a timing plan to optimize movement through intersections. The signals then share plans with neighboring signals to create coordinated actions.

The initial focus of Surtrac was to utilize traffic theory and artificial intelligence (AI) to optimize the coordination of traffic lights and reduce congestion, but the team received feedback that citizens felt like the technology only benefited vehicles and did not consider pedestrians needs. The technology now optimizes many modes of travel, keeping vehicles, cyclists, pedestrians, and transit moving and safe.

Since Surtrac has been deployed throughout the city, travel time has been reduced by 25%, braking has been reduced by 30%, and idling has been reduced by 40%. The app also communicates with traffic lights to improve mobility for people with disabilities.

Next time you’re at the Pittsburgh International Airport, check out the Metro21 display to see how Carnegie Mellon and the city of Pittsburgh are collaborating to build a smarter future!

To learn more, visit these links!

Surtrac 2.0 project page –

Traffic21 –