Evaluating bicycle–vehicle conflicts and delays on urban streets with bike lane and on-street parking

Spaces for cycling on urban streets are usually limited especially when on-street parking vehicles exist. As bicycle flow increases, some bikes are forced to run closely to automobiles resulting in conflicts between different road users and travel delay. This study aims to investigate the bicycle–vehicle conflicts in different traffic situations and how those conflicts increase travel delay. To this end, the cellular automation (CA) model is developed and calibrated to simulate the maneuvers of bikes and vehicles. Results show that there are mainly two types of conflicts between bikes and vehicles, namely the frictional conflicts and blocking conflicts. The frequency of the two conflicts is affected by the density of bicycle and vehicle traffic as well as the width of bike lane. Vehicular delays are evaluated for different traffic situations with the consideration of different occupations of parked vehicles. Policy suggestions regarding the bike lane design and parking hour permit are discussed to reduce the conflicts and delay.