User Behavior and Perceptions at Intersections with Turning and Mixing Zones on Protected Bike Lanes

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An acknowledged challenge with protected bike lanes in the U.S. is that even though the segment is separated from traffic, bicyclists must merge or interact with turning traffic at intersections unless all movements are signalized. This paper presents a comparison of five different intersection designs for protected bike lanes at intersections without bicycle signals. They represent different ideas for how to mix and interact bicycles and motor vehicles. The designs communicate to road users how this interaction is to occur with lane striping, green pavement markings, shared lane-use markings (sharrows), and with vertical flexpost delineators. In the paper, the designs are divided into “mixing zones” and “turning zones with a through bike lane” for evaluation purposes. The paper compares and contrast the designs using observed user behavior (from 78 hours of video were analyzed, in which 6,082 bicyclists and 7,574 turning vehicles were observed) and self-reported behaviors and comprehension (from 1,245 nearby residents and 690 intercepted bicyclists). Overall, the evaluation suggests there are benefits to clear demarcation of the entry to the merge zone for bicycles and cars and to creating a semi protected through bicycle lane.


Submitted for presentation at the Annual Meeting and publication in the Journal of the Transportation Research Board

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