A statistics and reaction time based framework for impact prediction of automated vehicles on road safety of vulnerable road users

We present an easy to implement method to estimate safety impacts of the introduction of automated vehicles (AVs) on crashes between cars and vulnerable road users (VRUs). Our approach is based on utilizing the power model of the relation between driven speeds and injury crashes, as well as a formula tying reaction times and deceleration capacity to braking distances. Braking distances are used to transform improvements in reaction time into an equivalent speed and quantitative impacts are then derived from the power model. Additionally, the share of injury crash causes assumed to be eliminated by AVs is removed from injury crash estimates. This results in a dose-response curve of the impact of market penetration of AVs on VRU injury crashes. This approach to safety impact estimation can serve to augment simulation results, such as would be produced by microsimulation software like AIMSUN, by the safety impacts on VRUs.