The ideal vulnerable road user - a study of parameters affecting VRU detection

Advanced Driving Assistance Systems (ADAS) have the potential to reduce occurrences and severity of collisions with Vulnerable Road Users (VRUs). However, the nearly infinite number of possible VRU visual appearances (e.g., size, clothing, accessories) represent a technical challenge as systems need to correctly detect and identify VRUs to take adequate mitigation measures. The aim of this study was to determine, through track testing, which parameters affect systems' capabilities in detecting pedestrians.

The standardized articulated adult male pedestrian (EPTa) and seven-year-old articulated child pedestrian (EPTc) targets were used as the control group. Evaluations on the track followed the Euro NCAP AEB-VRU test protocols, and derivatives thereof. An iterative test approach was used to benchmark the detection capabilities of systems with variations in target configuration and environmental conditions against the control group (baseline condition). Over 1,000 track tests using 24 configurations and 13 vehicles (model years 2019-2021) were conducted. The environmental conditions included nighttime and snow-covered roads. Pedestrians were dressed in winter clothing and/or equipped with accessories, including a hat, jackets of different colors, backpack, umbrella, and a scooter. Other scenarios involved parked vehicles as obstructions or using multiple pedestrian targets (to simulate a parent crossing the road with child or a crowd waiting at an intersection) to challenge the vehicles with realistic urban-like scenarios.

This study illustrates how the variation of parameters outside the baseline condition can affect a vehicles' safety performance. Weather conditions and urban-like scenarios on the test track affected some systems more than others. The validity of these findings is however limited by the small vehicle sample size and number of tests performed per scenario.

In Canada, vehicles are exposed to less-than-ideal road conditions and a wide range of pedestrian profiles. The vehicles tested demonstrated various levels of performance and capabilities when mitigating collisions with pedestrians. The research illustrates the safety risks associated with weather and types of VRUs.