Roundabouts are widely acknowledged to be effective at reducing travel speeds. These lower speeds are one of the
reasons why roundabouts tend to experience significantly fewer injuries and fatalities as compared to other types of
intersection control. However, there is limited research as to how speeds vary between roundabouts, signalized, and all-
way stop-controlled intersections. To better understand these differences, this study compares travel speeds between
roundabouts, signalized, and all-way stop-controlled intersections in Minnesota. At signalized intersections, speed data
are analyzed separately for vehicles arriving during the red and green phases. Multiple linear regression models are
estimated to examine average speeds and the deceleration rates at the entry approach, as well as average speeds and
acceleration rates on the exit approach. The results show that drivers begin reducing their speeds further upstream of
roundabouts, and speeds are also lower downstream of the roundabout as compared to other intersection types. This
reinforces research on the traffic-calming effects of roundabouts. At signalized intersections, driver deceleration behavior
is dependent on the signal phase during arrival (later, more rapid deceleration during green arrival or earlier, gradual
deceleration during red arrival). In contrast, behavior is comparable to roundabouts at all-way stop-controlled
intersections, though drivers tended to brake nearer to the intersection at these locations. Ultimately, this study provides
insights into how intersection design can influence driver speed selection and achieve target speeds.

Infrastructure Assets: Highway Assets
Resource Types: Research Report
Capabilities: Tools & Technology
Management Processes: Monitoring & Adjustment, Performance Based Planning & Programming