Impacts of Connected and Automated Vehicles on Road Safety and Efficiency: A Systematic Literature Review

Connected and automated vehicles (CAVs), in the context of cooperative intelligent transportation systems (C-ITS), are capable of exchanging information with each other and the infrastructure. They can also form platoons that can drive with shorter time headways resulting in potential higher capacity, smoother flow, less fuel consumption, and reduction in collisions. However, the literature assessing their impacts is still fragmented and does not provide a solid evidence base about their potential contributions, particularly that they are not widely deployed yet. This study aims to establish this evidence using a systematic literature review (SLR) of the relevant body of knowledge. In this paper, 347 journal publications from 2000 to 2021, are analyzed and critiqued. Comprehensive bibliographic and co-citation analyses are conducted to uncover the key findings and bring out a valid and balanced perspective of CAVs and their impacts on traffic operations. A co-citation analysis of the body of knowledge on this topic resulted in the formation of four main clusters of research focus that included safety, efficiency, communication, and technology. This SLR presents an unbiased and objective summary of scientific findings on the topic and serves as a starting point for future investigations on CAVs by identifying research gaps, limitations and challenges, and potential areas of research to overcome these challenges.