At signalized intersections, permitted left turns (i.e., on a green ball, after yielding) across multiple through lanes and across a separated bike lane or bike path present a threat to bicyclist safety. A conflict study of two such intersections with a bidirectional bike path found that when cyclists cross while a vehicle is ready to turn left and there is no opposing through traffic to block it, the chance of the left-turning motorist yielding safely was only 9%, and the chance of their yielding at all—including yielding only after beginning the turn, then stopping in the opposing through lanes—was still only 37%. Motorist non-yielding rates were worse toward bikes arriving during green, toward bikes approaching from the opposite direction (i.e., riding on the right side of the road), and toward bikes facing a queue with multiple left turning vehicles. Of 112 cyclists who arrived on green when there was at least one left-turning car, but no opposing through traffic blocking it, 73 had to slow or stop to avoid a collision. Although these conflicts could be essentially eliminated using protected-only left turn phasing (turn on green arrow), common existing criteria prefer permitted left turns to reduce vehicular delay. A case study shows how, by considering multiple signalization alternatives, it can be possible to convert left turns to protected-only phasing without imposing a substantial delay burden on vehicles or other road users.
Risk to Bicyclists in a Separated Path from Left Turns across Multiple Lanes: A Case for Protected-Only Left Turns
Transportation Research Record: Journal of the Transportation Research Board
Transportation Research Record: Journal of the Transportation Research Board ; 2675 , 10 ; 174-183
2021-05-05
Article (Journal)
Electronic Resource
English
Springer Verlag | 2020
|Estimation of Uniform Delay of Permitted Left Turns from Exclusive Turn Lanes
Online Contents | 2006
|Estimation of Uniform Delay of Permitted Left Turns from Exclusive Turn Lanes
British Library Online Contents | 2006
|British Library Online Contents | 2005
|