Pittsburgh Develops Smart Traffic Signals, Reduces Emissions 20%

Photo credit. Green Building Alliance

Everyone knows the frustration of sitting in gridlock. Pittsburgh-based Rapid Flow Technology’s Surtrac has developed smart traffic signals that adapt to changing traffic conditions to keep traffic moving.

These new traffic signals, sponsored through the Traffic21 Initiative at Carnegie Mellon University, have already expanded from nine in 2012 to forty-seven this year spanning from East Liberty to Downtown Pittsburgh. Since these traffic lights adapt to traffic patterns, they cut down on cars idling at lights. By their own estimates, Surtrac is reducing emissions by 20%, increasing the urban air quality.

What sets Surtrac’s lights apart is that they are decentralized and “each intersection allocates its green time independently based on actual incoming vehicle flows” and then that data is “communicated to neighboring intersections to increase their visibility of future incoming traffic.” Decentralization will also make expansion easier, helping Surtrac grow to the rest of Pittsburgh and eventually nationwide.

The next project for Surtrac involves monitoring cruising—when drivers ‘circle the block’ to look for parking. They are developing solutions to detect and measure the frequency of cruising for parking and its effects on congestion. Then they will work to integrate solutions for cruising into their traffic flow sensors.

Perhaps more importantly than decreasing frustrating, the increased air quality from reduced emissions will help Pittsburgh’s already-poor air quality improve. Particularly in denser urban neighborhoods, these street lights will improve the quality of life by making the streets more hospitable to pedestrians and bikers.

The inventors of Surtrac have moved closer to their traffic lights in East Liberty and formed Rapid Flow Technology, LLC which handles the distribution of the Surtrac system. The Henry L. Hillman Foundation, The Heinz Endowments, and the Richard King Mellon Foundation are providing funding for the project.


Contact: Stephen Smith, Ph.D. Chief Executive Officer.

Email:, Phone: (412) 268-8811


About Rapid Flow Technologies:

Rapid Flow Technologies LLC has recently spun out of Carnegie Mellon University with the goal of introducing new Intelligent Transportation Systems (ITS) technologies into the marketplace. Rapid Flow was created to commercialize the Surtrac adaptive traffic signal control technology developed in the Robotics Institute at Carnegie Mellon as part of the Traffic21 research initiative. The company’s founders include the original inventors of Surtrac, who have successfully expanded the initial pilot deployment of Surtrac in Pittsburgh to a network of 47 intersections over the past three years. Rapid Flow holds an exclusive license to the patented Surtrac technology from Carnegie Mellon University, and the University has a stake in the company. In addition to Surtrac, Rapid Flow is also engaged in the development of ubiquitous Bluetooth AVI sensor network technology for ITS performance modeling and other applications through a Small Business Innovation Research (SBIR) grant from the U.S. Department of Transportation.