Study: Darkness a Blind Spot for Pedestrian Detection Systems

Studies have shown that advanced safety systems save lives, but according to the Insurance Institute for Highway Safety, it’s a little more complicated for pedestrian detection systems. A new IIHS study looked at real-world pedestrian crashes and determined that automatic emergency braking systems with pedestrian detection work during the daytime, but they aren’t very effective at night. The results are alarming given the agency’s data show most fatal pedestrian crashes occur in the dark.

Related: IIHS Toughens Up Crash Tests; Many SUVs Fail

Automatic emergency braking systems with pedestrian detection use cameras, radar or a combination of the two to detect and warn drivers when there’s a pedestrian in the car’s path. The systems can then apply the brakes automatically to prevent or mitigate a crash.

In the IIHS study, researchers looked at nearly 1,500 police-reported crashes involving various model-year 2017-20 vehicles and compared pedestrian crash rates for identical vehicles equipped with and without the pedestrian systems. (It wasn’t immediately clear if the agency had visibility into whether any drivers of the AEB-equipped vehicles had deactivated their systems at the time of the crash.) Researchers analyzed how the technology works in several areas, such as crash severity, light condition, speed limit and whether the vehicle was turning.

The agency’s study determined that in all light conditions, pedestrian crash rates were 27% lower for vehicles equipped with the pedestrian-detecting AEB than for unequipped vehicles. However, when the researchers looked only at pedestrian crashes that occurred at night on roads without streetlights, they found no difference in crash risk for vehicles with and without the systems.

“This is the first real-world study of pedestrian AEB to cover a broad range of manufacturers, and it proves the technology is eliminating crashes,” said Jessica Cicchino, vice president of research at IIHS and the study’s author. “Unfortunately, it also shows these systems are much less effective in the dark, where three-quarters of fatal pedestrian crashes happen.”

And the systems are much needed. According to the agency, 6,205 pedestrians were killed in 2019, and 76,000 additional pedestrians were injured in crashes with a vehicle that year. The numbers are on an upward trend; IIHS reports that pedestrian crash deaths have risen 51% since 2009.

Inspiring Change

IIHS says it will continue to study the use of the systems at night, and it’s developing a nighttime test that will eventually factor into its two influential safety awards, Top Safety Pick and Top Safety Pick Plus. The agency has a history of raising benchmarks for crash tests and safety systems, and automakers have a similar history of rising to the challenge.

To wit, automakers made changes to their safety equipment in response to the agency’s tougher safety standards. In 2019, when IIHS started requiring an advanced or superior rating (the top two of four possible grades) for vehicle-to-pedestrian front crash prevention for any vehicle to get its awards, the technology was only available on 3 out of every 5 vehicles tested; the agency says pedestrian-detecting AEB is now available on nearly 9 in 10 model-year 2021 vehicles.

“The daylight test has helped drive the adoption of this technology,” said David Aylor, manager of active-safety testing at the agency. “But the goal of our ratings is always to address as many real-world injuries and fatalities as possible — and that means we need to test these systems at night.”

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New Test Planned

In a pilot of IIHS’ new nighttime pedestrian crash test, the agency’s research team tested the pedestrian detections systems of eight SUVs equipped with a variety of different pedestrian detection systems: radar, cameras or a combination of the two. The vehicles tested were the 2019 Subaru Forester, 2019 Volvo XC40, 2020 Honda CR-V, 2020 Hyundai Venue, 2021 Chevrolet Trailblazer, 2021 Ford Bronco Sport, 2021 Toyota C-HR and 2022 Volkswagen Taos.

IIHS tested each vehicle twice, first using high-beam headlights and then using low beams. None of the systems worked well in the dark, IIHS said; although some worked better than others, there was no single type of technology that got better results.

For example, the C-HR and Bronco Sport performed best in the test, and both systems use a combination of camera and radar. However, it’s not that simple: Other SUVs tested — such as the Forester and Trailblazer, which employ camera-only systems without radar — achieved similar nighttime results as the CR-V, XC40 and Venue, all of which use camera and radar.

The results don’t paint a clear picture, which is why IIHS will continue to study the systems ahead of the test’s official rollout. Joe Young, a spokesperson for IIHS, told Cars.com that the new test will factor into the agency’s Top Safety Pick awards beginning in 2023.

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