The effectiveness of forward collision warning systems in detecting real-world passenger and nonpassenger vehicles relative to a surrogate vehicle target

April 2024

Automatic emergency braking (AEB) and forward collision warning (FCW) reduce the incidence of police-reported rear-end crashes by 27% to 50%, but these systems may not be effective for preventing rear-end crashes with nonpassenger vehicles. The Insurance Institute for Highway Safety (IIHS) and Transport Canada evaluated FCW performance with 12 nonpassenger and seven passenger vehicle or surrogate vehicle targets in five model year 2021–2022 vehicles. The presence and timing of an FCW was measured as a test vehicle traveling 50, 60, or 70 km/h approached a stationary target ahead in the lane center. Equivalence testing was used to evaluate whether the proportion of trials with an FCW (within ± 0.20) and the average time-to-collision of the warning (within ± 0.23 s) for each target was meaningfully different from a passenger-car global vehicle target (GVT). A similar approach was used to determine if FCW performance was reproducible between three targets tested by both IIHS and Transport Canada and was equivalent between surrogate car and motorcycle targets produced by different companies. FCW systems provided fewer and later warnings when the vehicles approached nonpassenger vehicles compared with the GVT. Results were reproducible between IIHS and Transport Canada, but FCW performance with passenger car and motorcycle surrogate targets representing the same vehicle were not always equivalent. Testing organizations should evaluate AEB and FCW systems with nonpassenger vehicle targets to ensure that AEB and FCW performance observed with passenger vehicles extends to other vehicle types, particularly motorcycles and medium or large trucks that are commonly struck in fatal rear-end crashes.