Evaluation of Traffic Safety for Heavy Commercial Vehicles at Roundabouts in Minnesota

Modern roundabouts have been shown to be one of the safest methods of control for at-grade intersections. An evaluation of traffic safety at roundabouts published by MnDOT in 2017 shows substantial decreases in fatal and serious injury crashes at intersections after installation of a roundabout. Despite these benefits, concerns have been raised from citizens, commercial motor vehicle (CMV) drivers, and other stakeholders about the propensity for roundabouts to cause more rollover crashes for larger vehicles. The purpose of this evaluation is to further evaluate the safety of heavy commercial vehicles at roundabouts, investigate whether rollover crashes are more likely to occur at roundabouts, and break down the most common characteristics for CMV crashes at roundabouts in Minnesota. This report includes the results of an analysis comparing roundabouts to signalized intersections. The results of this evaluation indicate that roundabouts continue to be one of the safest forms of intersection control for heavy commercial vehicles, especially when compared to traffic signal control. Although roundabouts have experienced a greater number of rollover crashes compared to intersections with traffic signal control, their installation results in a decrease in high-severity crashes.