Modelling and Simulation of Heterogeneous Traffic: An investigation of autonomous vehicles impact on heterogeneous traffic in terms of traffic flow and safety

Abstract

The development of Autonomous vehicles has intensified during recent years, and autonomous vehicles is believed to be a common sight on public roads in the near future. It is safe to say that autonomous vehicles will revolutionize the transportation field in multiple ways, such as improved transportation comfort and improved traffic safety. The aim of this study is to investigate how autonomous vehicles will impact heterogeneous traffic in terms of traffic flow and safety. In the context of this study, heterogeneous traffic is defined as traffic situations with different vehicle types, both manually driven and autonomous. To investigate how autonomous vehicles impacts the flow and safety of heterogeneous traffic, simulation models of manually driven vehicles and autonomous vehicles was calibrated. The simulation models, which were calibrated based on a naturalistic data-set, represent cars and trucks which takes the preceding vehicle type under consideration. Simulations were executed in SUMO with various penetration rates of autonomous vehicles with the intention to analyze how the different penetration rates impact the heterogeneous traffic. The simulation results showed that the number of traffic conflicts tends to decrease as the penetration rate of autonomous vehicles increase for the same mean road speed. Also, the results showed that the mean road speed increase as the penetration rate of autonomous vehicles increase for the same vehicle flow rate. The difference in mean road speed for the different penetration rates increases as the vehicle flow rate gets bigger. This leads to the number of conflicts increase as the penetration rate increase when the vehicle flow rates are high. These results suggest the autonomous vehicles have the potential to improve the traffic safety by decreasing the number of conflicts and to improve the traffic flow by increasing the mean road speed and therefore lessen the travel time. However, the mean speed needs to be limited, or else the number of conflicts will significantly increase.