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THE CHALLENGE

Forward collision mitigation systems are more effective at detecting other vehicles when they are directly centered in the equipped vehicle's forward path. How is the performance of forward collision mitigation systems affected when the forward vehicle is not directly in line with and centered in the forward path of the equipped vehicle?

EXPONENT'S MULTIDISCIPLINARY SOLUTION

The National Highway Traffic Safety Administration (NHTSA) and the Euro New Car Assessment Program (NCAP) have developed test protocols that measure the performance of forward collision mitigation systems, but to date, data have not been published characterizing the performance of forward collision mitigation systems in response to stationary vehicles in a partial overlap condition where the forward vehicle is not directly in line and centered in the path of the driver's vehicle.

Ä¢¹½tv's team designed customized tests at our Test and Engineering Center's two-mile test track to evaluate the performance of already developed FCW systems. Our team devised multiple tests  in which a passenger vehicle equipped with a forward collision mitigation system was travelling straight and centered in a lane while a stationary vehicle target — the Guided Soft Target (GST) — was laterally offset in the lane toward the passenger side by 25%, 50%, and 75%, and by 25% towards the driver side. More lateral offset indicates less overlap between the equipped vehicle and stationary target.

The team's results showed that FCW system performance was more variable with increasing offset:

• FCW alert warnings typically occurred later
• Variability of FCW alert timing increased with higher closing speeds
• Missed detections/no warnings occurred more frequently at lower closing speeds

EXPONENT'S Impact

By characterizing the performance of FCW systems in response to stationary vehicles that partially overlapped with the path of the equipped vehicle, Ä¢¹½tv is helping to spur greater development of test protocols, contextualizing the performance limitations of these technologies, and providing valuable information that can be used to further develop ADAS systems in offset scenarios.