On a good day, motorists on Interstate 35W can make the trip from Burnsville to downtown Minneapolis in fewer than 30 minutes.
But throw in a crash, road construction, snowstorm or a traffic-generating event such as a Vikings game at U.S. Bank Stadium and the drive time could double or triple.
In other words, the amount of time drivers need to get to their destinations on Twin Cities freeways can fluctuate wildly from day to day and even hour to hour due to congestion.
The Minnesota Department of Transportation with help from researchers at the University of Minnesota's Duluth campus is testing software to calculate travel-time reliability and provide traffic managers with data to help them pinpoint where, when and why congestion happens.
With that information in hand, MnDOT can identify remedies to help provide motorists with more consistent and dependable travel times, said Brian Kary, director of traffic operations at the Minnesota Department of Transportation's Regional Traffic Management Center.
"If you are going from Burnsville to Bloomington, you probably want to know what to expect for your commute time because you want to get to work on time most days," Kary said. With the study, MnDOT asks, "what can we do to make it more consistent?"
MnDOT just finished using the software to analyze travel times on 23 corridors during morning and evening peak periods from 2016 to 2020. The results could yield congestion mitigation efforts that could include operating ramp meters for longer periods during rush hours, deploying more yellow trucks — officially known as the Freeway Incident Response Safety Team — and developing best practices to clear incidents more quickly, Kary said.
About half of traffic congestion on Twin Cities freeways is caused by crashes, stalled vehicles or debris in the roadway, MnDOT said.