At signalized intersections, diagonally left-turning bicyclists impede through automobile trafficand may experience significant delay. As an alternative to diagonal left-turns, Copenhagen Leftoperations can be used, in which left-turning bicyclists are required to go straight along withthrough automobiles from the same approach, stop, wait for the green interval for the cross street,and then go straight along the cross street to finish the maneuver. The objective of this study wasto compare Copenhagen Left with diagonal left-turn maneuver in terms of impacts on capacity ofautomobile traffic and delay of bicyclists. To this end, an analytical capacity model wasdeveloped based on the observed behavioral patterns of automobiles when impeded bydiagonally left-turning bicyclists. Micro-simulation models were used to assess delays incurredto bicyclists under both Copenhagen Left and diagonal left-turn operations. Numerical resultsevidenced that the capacities estimated by the proposed model were consistent with microsimulationmethod. While Copenhagen Left enhances capacities of automobiles, it is notuniversally appropriate for all situations. Copenhagen Left can considerably increase delay forleft-turning bicyclists at low-volume, small-sized intersections, which may lead to lowcompliance rate by bicyclists. A successful implementation of Copenhagen Left does not relyonly on proven operational benefits, but also on sufficient storage space for the resultingstanding bicyclists, clear pavement striping and signage, and effective education for the travelingpublic.
展开▼
