Study finds 511 Systems can reduce traffic delays by 2.57 percent on average.
Longitudinal study of 511 systems in the United States finds widespread benefits and cost savings.
Made Public Date


United States

Mitigating Traffic Congestion: The Role of Intelligent Transportation Systems

Summary Information

To empirically assess the impact of ITS on traffic congestion, a longitudinal dataset of 99 U.S. Metropolitan Statistical Areas (MSAs) over a period of 21 years from 1994 to 2014 were consolidated by integrating multiple data sources. The unit of analysis is an MSA as designated by the U.S. Census Bureau. 

511 systems, also called traveler information systems, were one of the first intelligent transportation system (ITS) technologies to see widespread deployment in the United States. These systems began as telephone based systems where travelers, specifically motorists, could dial 5-1-1 and get travel information such as traffic information. Over time these systems have evolved into complex travel information systems that use cameras, sensors, and other data sources to monitor and, in some cases, dynamically reroute, traffic in real-time. Additionally, some 511 systems now provide non-motorist oriented information such as public transport information, among other things.


Interested in the benefits of 511 systems, a research team at the London School of Economics analyzed the effects of these systems on traffic congestion and air pollution. To do this the researchers used 21 years of traffic data, specifically Texas A & M’s Annual Urban Mobility Scorecard and Highway Performance Monitoring Systems data, for the 99 largest Metropolitan Statistical Areas (MSAs) in the United States. These data were used to build a series of econometric models where the main dependent variable was congestion and the main independent variable was the presence of 511 systems.


Results suggest that 511 system adoption resulted in a 2.86 percent decrease in traffic congestion costs and 2.57 percent decrease in traffic delays, on average per MSA.

Goal Areas