Intelligent Traffic Signal Project Uses Connected Vehicles

Burney Simpson

Researchers at the University of Arizona are exploring an intelligent traffic control system that puts a priority on certain connected vehicles and includes a pedestrian smartphone application for the blind, according to a presentation this week at the Transportation Research Board 94th Annual Meeting in Washington, D.C.


The Multi Modal Intelligent Traffic Signal System (MMITSS) is designed to review such concepts as queue warning, speed harmonization, cooperative-adaptive cruise control, and eco-driving, according to K. Larry Head, associate professor at the university’s College of Engineering, Department of Systems and Industrial Engineering, a leader on the project.

Head said that the project’s objective is to develop a comprehensive traffic signal system that serves multiple modes of transportation including passenger vehicles, transit, emergency vehicles, freight fleets (trucks), and pedestrians.


Along with Head’s group, contributors to the technical aspect of the project include the University of California Berkeley, the U.S. Department of Transportation, the California Department of Transportation (CALTRANS), and the firms Savari Networks and Econolite.

The MMITSS is using real-time performance measure to review data on traffic volume, delays, throughput and stops in two sections of a four-way intersection. Each section has its own priority in types of traffic, and a priority hierarchy for vehicles. The priority for Section 1 is trucks, and the priority hierarchy is rail crossings, emergency vehicles, trucks, passenger vehicles, transit, and pedestrians. Sections 2’s priority is transit and pedestrians, and its priority hierarchy is rail crossings, emergency vehicles, transit, pedestrians, passenger vehicles, and trucks.


The vehicles in the project have connected vehicle equipment and an aftermarket safety device on board. Communications between the vehicles and the connected infrastructure roadside equipment (RSE) is done with Dedicated Short-Range Communication (DSRC) 5.9 GHz radio equipment. A basic safety message (BSM) is broadcast 10 times a second between vehicles and the infrastructure equipment.


The pedestrian smartphone app is designed to give the user auditory and haptic feedback that allows them to align with the crosswalk, send a call for service, be given a walk signal, and to understand the countdown to a signal change. Haptic refers to tactile technology that recreates the sense of touch with vibrations, motions or forces.


Funding for the project is provided by the Federal Highway Administration, along with the departments of transportation of the states of Florida, Michigan, Minnesota, and Virginia and of Maricopa (Ariz.) County, and CALTRANS.