Assessing the Effectiveness of Augmented Reality Warnings for Improving Safety at Highway Merging Zones in a Connected Environment

The merging process of vehicles moving from the on-ramp to the right lane of a highway is quite critical at interchanges for both safety and operational efficiency. Several studies have emphasized the importance of merging zones at interchanges, identifying them as major sites of conflicts between passing and entering vehicles. Incorrect assessment of gaps and precedence in these zones can result in serious collisions and traffic disruptions at interchanges. This study looks at how effective Augmented Reality (AR) solutions in a connected environment are in improving safety at merging zones, helping drivers keep a safe distance from vehicles entering the highway from on-ramps. In a driving simulation study, four different safety measures are evaluated: i) a vehicle-to-vehicle spacing measurement support, which integrates a Variable Message Signs panel (VMS) with a new type of road pavement marking; ii) a Head-Up Display (HUD) that projects a static symbol onto the vehicle windshield, advising the driver to maintain a safe distance from the entering vehicle; iii) a connected vehicle system that integrates AR technology consisting of a dynamic symbol on the road surface, which provides the driver with additional visual cues about the actual longitudinal distance from the entering vehicle; iv) the same AR-based system with an additional audible warning. The driving behavior of forty-four participants in four different configurations with the safety measures was compared with their behavior in a configuration without any measures (baseline condition). The results demonstrated a significant positive impact from all tested measures, with the most effective solution being AR systems, which demonstrated the ability to assist drivers in adjusting their distance from the entering vehicles. This study confirms the high potentialities of AR technologies and connected vehicles in enhancing the overall safety of road networks, particularly in high-risk scenarios and challenging maneuvers.