FHWA: Making Our Roads Safer One Countermeasure at a Time

https://safety.fhwa.dot.gov/ provencountermeasures. 8. Left and Right Turn Lanes at Two-Way Stop-Controlled Intersections SAFETY BENEFITS: LEFT-TURNLANES 28-48% Reduction in total crashes RIGHT-TURNLANES 14-26% Reduction in total crashes INTERSECTIONS | PROVEN SAFETY COUNTERMEASURES Auxiliary turn lanes— either for lef turns or right turns—provide physical separation between turning trafic that is slowing or stopped and adjacent through trafic at approaches to intersections. Turn lanes can be designed to provide for deceleration prior to a turn, as well as for storage of vehicles that are stopped and waiting for the opportunity to complete a turn. While turn lanes provide measurable safety and operational benefits at many types of intersections, they are particularly helpful at two-way stop-controlled intersections. Crashes occurring at these intersections are ofen related to turning maneuvers. Since the major route trafic is free flowing and typically travels at higher speeds, crashes that do occur are ofen severe. The main crash types include collisions of vehicles turning lef across opposing through trafic and rear-end collisions of vehicles turning lef or right with other vehicles following closely behind. Turn lanes reduce the potential for these types of crashes. Installing lef-turn lanes and/or right-turn lanes should be considered for the major road approaches for improving safety at both three- and four- leg intersections with two-way stop control on the minor road, where significant turning volumes exist, or where there is a history of turn-related crashes. Pedestrian and bicyclist safety and convenience should also be considered when adding turn lanes at an intersection. Example of lef-turn lanes. Source: FHWA Example of a right-turn lane. Source: FHWA Source: Highway Safety Manual