Advanced Driver Assistance Systems (ADAS) are vehicle-based intelligent safety systems, developed and deployed by vehicle manufacturers, which have the potential to improve road safety in terms of crash avoidance, crash severity reduction, and protection. This study examined the technical feasibility of various retrofit ADAS, and specifically evaluated Forward Collision Warning (FCW), Lane Departure Warning (LDW), Advanced Driver Distraction Warning (DDR-ADR), Speed Limit Information (SLI), Reversing Detection (REV), Tire Pressure Monitoring (TPM) system, Vulnerable Road User Detection and Warning on front and side of vehicle (VIS-DET), Turn Assistant for trucks, and 112 eCall. Some of the ADAS considered in this study have been available and factory-fitted in vehicles since 2015 and 2018, and some are planned to be implemented in 2022 and 2024. The current penetration rates of ADAS in the European Union (EU) vehicle fleet and their expected development over time were assessed, and various policy measures and their expected effects were developed. The expected impacts of retrofitting ADAS under two different policy options were tested in a cost-benefit analysis (CBA).