Safety and Capacity Analysis of Automated and Manual Highway Systems

This paper compares safety of automated and manual highway systems with respect to resulting rear-end collision frequency and severity. Safety is related to driver, vehicle and highway operating characteristics. Our safety analysis method maps the variation in these operating characteristics, modeled by probability distributions, to the probability and severity of the first rear-end crash due to a hard braking disturbance on the highway. The results show that automated driving is safer than the most alert manual drivers, at similar speeds and capacities. We also present a detailed safety-capacity trade-off study for four different automated highway system concepts that differ in their information structure and separation policy. This study quantifies the impact of inter-vehicle cooperation and operating speed of the Automated Highway System (AHS). It also compares and contrasts the safety characteristics of individual vehicle and platoon based Automated Highway Systems.