Advancing safety through connected and autonomous vehicles: a meta-analysis of market penetration and safety improvement rates from 2015 to 2024

Abstract

The field of Connected and Autonomous Vehicles (CAVs) promises to improve road safety through advanced communication technologies and data sharing. This study addresses the need for a clearer understanding of the relationship between CAV Market Penetration Rates (MPRs) and Safety Improvement Rates (SIRs) by conducting an updated meta-analysis that includes 49 studies published between 2015 and 2024. Across these studies, the primary focus of safety surrogate measures was on Time-to-Collision and Post Encroachment Time. We applied sensitivity analysis to refine the data and mitigate the effects of variability across simulation parameters and scenarios. A power function was identified as the most accurate model to describe the MPR–SIR relationship. At low market penetration rates, safety gains are modest; mid-range adoption shows that raw findings often overestimate safety benefits; and at high adoption levels, benefits become substantial and more consistent. The findings inform transportation planners and policymakers on the safety potential of CAVs, emphasizing the importance of high market penetration to realize meaningful safety improvements.