Open Access

Vinu Vijayakumaran Nair, Markus Rehmann, Stephan de la Rosa, Michael Sachse, Cristóbal CurioORCiD

• Timely detection of vulnerable road users (VRU) remains one of the toughest safety challenges as driving tasks shift from humans to automated systems. Beyond factors such as environmental visibility and road conditions, specific perceptual and behavioral characteristics of vulnerable road users could also compromise driver hazard perception. This study focuses on motion camouflage, a stealth strategy seen in animals in which a pursuer moves in such a way that its image on the target’s retina mimics the motion of a stationary object, thereby minimizing the optical cues that usually draw attention. Motion camouflage in driving scenarios refers to situations where, e.g., specific VRU movements make them less detectable to drivers. A virtual reality driving simulator was used to study how driver braking responses are affected by VRU motion trajectories under varying environmental conditions. Results show that VRU motion camouflage constitutes a fundamental gap in hazard perception, posing a risk that could potentially result in delayed detection and increased risk of accidents. Based on these findings, this paper provides a basis for developing more trustworthy advanced driver-assistance systems (ADAS) capable of recognizing and mitigating risks due to such perceptual vulnerabilities.