Micro-simulation insights into the safety and operational benefits of autonomous vehicles

Several past studies showed that Autonomous Vehicles(AVs)can reduce crash risk,stop-and-go traffic,and travel time.To analyze the safety benefits of AVs,most of the researchers proposed algorithms and simulation-based techniques.However,these studies have not assessed the safety benefits of AVs for different vehicle types under heterogeneous conditions.With this opportunity,this study focuses on the benefits of AVs in terms of safety for different penetration rates under heterogeneous conditions.This study considered three driving logics during peak hour conditions to assess the performance of AVs in terms of safety.In VISSIM,default driving behavior models for AVs were adopted to consider cautious and all-knowing driving logic and the third driving logic(Atkins)was modeled in VISSIM using parameters adopted from the previous studies.To this end,using VISSIM,the travel time output results were obtained.Also,using Surrogate Safety Assessment Model(SSAM),conflicts were extracted from output trajectory files(VISSIM).The results suggest that“cautious driving logic”reduced travel time and crash risk significantly when compared to the other two driving logics during peak hour conditions.Furthermore,the statistical analysis clearly demonstrated that“cautious driving logic”differs significantly from the other two driving logics.When Market Penetration Rates(MPR)were 50%or greater,the“cautious driving logic”significantly outperforms the other two driving logics.The results highlight that adopting“cautious driving logic”at an expressway may significantly increase safety at higher AV penetration rates(above 50%).