Modeling the performance of restricted crossing U-turn intersections including the effects of connected and autonomous vehicles: a case study in California.

Despite numerous studies demonstrating the effectiveness of restricted crossing U-turn (RCUT) intersection design, its implementation remains close to zero in some large states (e.g., California). The study included four locations on high-speed rural expressways (highways with partial access control) in California. The operational evaluation relies on microscopic simulation models of existing two-way stop-controlled (TWSC) intersections and alternate RCUT designs used to estimate network-wide performance measures. Two series of simulation scenarios were tested: (1) scenarios with no connected and autonomous vehicles (CAVs) and (2) scenarios with different SAE International Level 4 CAV market penetration rates (MPRs) to help policymakers and practitioners in future planning strategies. The microsimulation models were also used to generate trajectory data to create a surrogate measure-based approach. Based on the results, the RCUT designs reduced or eliminated the more severe crossing conflicts. Similar vehicle travel times were identified in various CAV MPRs except for one of the locations with challenging geometric features, where travel time increased at higher CAV MPRs. [ABSTRACT FROM AUTHOR]