Simulation Research on Operation and Safety Characteristics of Urban Traffic Flow with Connected and Autonomous Vehicles

The objective of this study was to analyze the impact of connected and autonomous vehicles(CAVs) on urban traffic flow. Based on Nagle-Schreckenberg meta-cellular model and Gipps safety distance model, a single-lane meta-cellular automaton model was developed to simulate urban traffic flow, which consists of CAVs and manually driven vehicles(MDVs). In particular, reaction time of conventional drivers was considered to make the cellular automaton model closer to the real traffic flow, and operation rules for CAVs and MDVs were established according to Gipps safety distance model. Simulation was conducted under various reaction time and market penetration rates to quantitatively analyze the traffic running and safety characteristics. The simulation results illuminate that CAVs with low reaction time make traffic flow capacity and velocity increases obviously before the market rate reaches 40%. In terms of traffic safety characteristics, velocity dispersion and TTC results show that CAVs with low reaction time would reduce traffic safety. The research results can provide references for traffic management and road design in the future.The objective of this study was to analyze the impact of connected and autonomous vehicles(CAVs) on urban traffic flow. Based on Nagle-Schreckenberg meta-cellular model and Gipps safety distance model, a single-lane meta-cellular automaton model was developed to simulate urban traffic flow, which consists of CAVs and manually driven vehicles(MDVs). In particular, reaction time of conventional drivers was considered to make the cellular automaton model closer to the real traffic flow, and operation rules for CAVs and MDVs were established according to Gipps safety distance model. Simulation was conducted under various reaction time and market penetration rates to quantitatively analyze the traffic running and safety characteristics. The simulation results illuminate that CAVs with low reaction time make traffic flow capacity and velocity increases obviously before the market rate reaches 40%. In terms of traffic safety characteristics, velocity dispersion and TTC results show that CAVs with low reaction time would reduce traffic safety. The research results can provide references for traffic management and road design in the future.