TRAFFIC SIGNALS: SMART traffic signals helping Minnesota DOT get timing down

Software upgrade driving down cost of advanced traffic analysis

September 24, 2013

New software for the Minnesota Department of Transportation’s (MnDOT) high-tech traffic signals is helping the department better measure traffic patterns, with deployment of the updated technology in progress at 50 intersections across the state.


The SMART Signal system (Systematic Monitoring of Arterial Road and Traffic Signals) collects and analyzes traffic data, ultimately gauging when and where backups occur on a given roadway. The new software upgrade—created by Henry Liu, associate professor of civil engineering at the University of Minnesota and original SMART Signal designer—allows direct retrieval of traffic data from the signal controllers without the need for any additional hardware.


With the new system in place, traffic engineers will be able to evaluate current signal timing plans based on queue length, level of service, travel time, speed, volume and delay. MnDOT metro traffic engineer Steve Misgen said this would allow MnDOT to determine how often they need to retime their signals; currently the department does so every three years.

Eventually, the hope is that the SMART Signal system can become part of a larger integrated corridor management (ICM) system. MnDOT continues to conduct research into the possibility, with traffic simulations yielding promising results.