By Arpita Sharma, MPP/MPL 2017

A new study on traffic lights was released on June 15, 2015. The study, conducted by Dr. Petros Ioannou, METRANS Associate Director of Research and Professor in the Department of Electrical Engineering at the University of Southern California, and funded by METRANS and USDOT, concludes that overall delay for all vehicles and pollution can be reduced by giving priority to trucks at traffic lights.

In the study, Ioannou developed a traffic light controller for road networks that takes into account the difference in size and dynamics between trucks and passenger vehicles. The traffic light controller optimizes the traffic light sequences, giving priority to trucks, minimizing the delays for all vehicles on the road. For example when a truck is approaching a green light that is about to turn red, it may be to the benefit of all vehicles in the network to extend the green light for the truck to pass through the intersection.  This action prevents the truck from stopping at the light and then accelerating again when the green comes back on.

The key difference between trucks and cars in navigating signalized intersections is that trucks require significantly longer time and distance to stop and then when they start again experience significantly lower acceleration rates.  From an environmental perspective, they also consume more fuel and generate more pollution when they must stop and then accelerate again.  Ioannou’s research demonstrates that implementation of the priority traffic light controller design in future roadway design projects may reduce traffic delays and pollution for all vehicles on the road.

A two page summary of Ioannou’s report can be found here.

The full report can be found here.

Petros Ioannou

Petros A. Ioannou received the B.Sc. degree with First Class Honors from University College, London, England, in 1978 and the M.S. and Ph.D. degrees from the University of Illinois, Urbana, Illinois, in 1980 and 1982, respectively. In 1982, Dr. Ioannou joined the Department of Electrical Engineering-Systems, University of Southern California, Los Angeles, California.  He is currently a Professor in the same Department and the Director of the Center of Advanced Transportation Technologies.  His research interests are in the areas of control and applications, adaptive and nonlinear systems, vehicle dynamics and control, intelligent transportation systems, marine transportation, congestion control of computer networks and neural networks.  He is currently an Associate Editor of the IEEE Transactions on Intelligent Transportation Systems, Associate Editor at Large of the IEEE Transactions on Automatic Control, Member of the Control System society on IEEE ITS Council Committee and Vice-Chairman of the IFAC Technical Committee on Transportation Systems.  Dr. Ioannou is a Fellow of IEEE and the author/co-author of 5 books and over 150 research papers in the area of controls, neural networks, nonlinear dynamical systems and intelligent transportation systems.

Ioannou can be reached at:

Petros Ioannou
Ming Hsieh Department of Electrical Engineering; USC Viterbi School of Engineering
University of Southern California
3740 McClintock Avenue, Hughes Aircraft Electrical Engineering Center (EEB) 200B
Los Angeles, CA 90089-2562
United States
[email protected]

Arpita Sharma

Arpita Sharma is a dual Master of Public Policy and Master of Planning Candidate at the USC Price School. She is interested in issues of health inequities, sustainable land use development and active transportation.  She expects to complete her degrees in May 2017. She can be reached at arpitasharma.net or at [email protected].