New Project: Effect of Centerlines on Prevailing Traffic Speeds of Low-Speed, Two-Lane, Two-Way Roads in Urban Contexts

Vehicle speed has a substantial influence on both the likelihood and severity of crashes involving nonmotorized road users. Reducing speeds on urban streets, in particular, enhances safety for the greatest number of vulnerable road users.

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Centerlines are generally required on roads based on lane width and traffic volume because they separate opposing traffic and improve driver lane positioning around curves, on bridges and against other potential obstacles. MnDOT and local transportation agencies want to explore whether the presence of centerlines impacts vehicle speeds on urban roads.

Identifying the road characteristics and contexts where centerlines impact driver speed will help optimize their use. Insight into using centerlines to help manage traffic speed on low-speed urban streets will support safety and mobility enhancements for nonmotorized users.

“This research is needed to understand the potential of centerlines as a tool to encourage slower speeds,” said Ken Johnson, assistant state traffic engineer, MnDOT Office of Traffic Engineering. “Results will help MnDOT and local agencies ensure urban roads are safe and accommodate the needs of all users.”

Objectives

In a new project, researchers will determine whether there is a relationship between the presence of centerlines and traffic speeds on low-speed, two-lane, two-way urban streets.

The objectives are:

Identify urban street study sites with varying attributes such as speed limit, traffic volume, land use context and parking availability
Use a range of methods, including lidar guns, video cameras and speed sensors, to collect speed data on street segments with and without centerlines
Analyze data to determine whether the presence of centerlines impact driver speeds
Develop guidance informing agencies about the street characteristics where centerlines impact traffic speeds