This study examines the challenges associated with deploying autonomous vehicles (AVs) in road tunnels, focusing on both operational aspects and vehicle-human interaction. This work explored that road tunnels present unique constraints, such as limited visibility and confined spaces, which necessitate careful consideration for AV integration. It is observed that factors like varying light conditions and restricted communication capabilities within tunnels impact AVs' performance. Additionally, the study investigates and categorizes challenges related to tunnel geometries, infrastructure modifications, sensor technologies, emergency situations, and human-machine interaction.
Furthermore, this work comprehensively explored academic and non-academic literature, gathering contemporary knowledge on AVs in road tunnels in one place to provide a foundational base for researchers on this topic. In this regard, the adopted methodological framework is also presented for researchers' review. The other notable contribution is to specifically highlight the critical operational issues of human-AV interaction in tunnel environments. In the last section, it also proposes potential solutions to these issues. In doing so, it keeps the directional approach open for other researchers as there are insightful risk-related implications for further research in this significant domain
