Leveraging Connected Vehicles to Enhance Traffic Responsive Traffic Signal Control

One of the earliest innovations promoted by the FHWA’s Every Day Counts initiative is adaptive signal control technology – adaptive because traffic flow can be regulated based on data transmitted by strategically-placed sensors to adjust the timing of red, yellow and green lights. The goal is to reduce congestion by creating smoother flow and improving travel times by progressively moving vehicles through green lights. A positive by-product is that emissions are reduced and fuel economy is improved.

With growing use of Connected Vehicles (CV) (vehicles typically equipped with communication technologies such as GPS to communicate with the driver, other cars and roadside infrastructure), researchers at Old Dominion University, Virginia Tech and Marshall University are exploring optimization of current adaptive signal control technology to estimate queue length and develop enhanced signal coordination through communication with CV sensors. The research focuses on Traffic Responsive Plan Selection (TRPS), an underutilized adaptive control product enabling the selection of pre-programmed traffic signal timing plans based on vehicle demand observed from selected vehicle detectors along a signalized corridor.

Using a signal system in Morgantown, WV as the test bed, the researchers tested algorithms for estimating queue lengths from vehicle trajectory data in real-time, estimating the state of the system in real-time, and communicating information back to the controllers to change the timing plans when appropriate. The field data collection work has been completed and the advanced TRPS plans are now being compared in a simulation environment to basic coordination timing plans and basic TRPS control option across various volume scenarios to estimate improvements in delay, emissions, and fuel consumption.

“Most intersections have timed signals to ensure traffic moves at a regular pace,” explained Mecit Cetin, director of the Transportation Research Institute at Old Dominion University and one of the project’s lead collaborators. “The beauty of using enhanced TRPS is the ability to develop a full range of scenarios, or traffic response plans, to modify the timing of the traffic signal. Think, for example, of a traffic signal near a movie theater. Traffic flow fluctuates from the norm when movie-goers leave the theater. Using CV data and the most appropriate plan, the traffic signal becomes responsive to queues in real-time. In other words, the traffic signal is responsive to the immediate problem.”

The goal is to develop guidelines for designing and operating TRPS to reduce fuel consumption and emissions while promoting the adoption of traffic responsive programs as a low-cost adaptive solution to reduce congestion.

For more information, contact Dr. Cetin at mcetin@odu.edu.