Dedicated Turning Lanes

Usage: Limited

Left-turns present a multifaceted challenge for all road users, necessitating careful navigation of oncoming traffic, sight distances, blind spots, and potential obstructions. These challenges are amplified at intersections with complex traffic dynamics and vehicle movements. Dedicated left-turn lanes effectively address these concerns by providing designated spaces for motorists to slow down, wait safely, and execute these turns, thus reducing congestion and collision risks for drivers, cyclists, and micromobility users.

Beyond delineating space, designing effective left-turn lanes involves integrating elements such as traffic signal synchronization, pedestrian crossings, and accommodations for cyclists and micromobility users. Incorporating these considerations creates safer, more efficient, and accessible streetscapes.
 

Amsterdam Avenue, Manhattan
Franklin Street and Quay Street, Brooklyn

Benefits

  • Enhance safety by providing space for vehicles to slow, wait, and turn, reducing collisions at intersections and minimizing conflicts with pedestrians to ensure safer crossings
  • Separating left-turn movements from through traffic enhances roadway efficiency and reduces congestion
     

Considerations

  • Must maintain safe crossings for pedestrians and avoid conflicts with cyclists and other micromobility users 
  • Careful consideration of intersection specific characteristics, including traffic volumes, historical collision data, and pedestrian and cyclist activities
     

Application

  • Intersections with high traffic volumes, where left-turn movements can impede the flow of through traffic
  • Intersections prone to left-turn conflicts, where turning vehicles must yield to oncoming traffic
  • Intersections with a history of left-turn related crashes should be prioritized to enhance safety and reduce the risk of future collisions
  • Intersections with heavy pedestrian activity require careful consideration when implementing turning lanes to ensure pedestrian safety 
  • Intersections along transit corridors, where buses or other public transportation vehicles make frequent stops or turns, may benefit from dedicated left-turn lanes to improve efficiency 
     

Design

  • Prioritize the safety and convenience of pedestrians and cyclists, including providing safe crossings, clear signage, and dedicated spaces for cyclists to wait and turn
  • Well-marked lanes and clear signage guide drivers and reduce last-minute lane changes
  • Dedicated signals and optimized timing improve safety and accommodate peak turning volumes
  • Turn lanes should be sufficient in length to prevent vehicle spillover into through lanes
  • Offset left-turn lanes improve sight-lines and reduce turn-related collision risks
     
↑