Safety Group: Pedestrian Detection Systems Don’t Work As Well At Night

By Sean Tucker 02/04/2022 8:51am

Automatic emergency braking (AEB) with pedestrian detection – those heavily advertised systems that stop a car from hitting a pedestrian even if the driver doesn’t hit the brakes fast enough – work well, according to one of America’s leading auto safety groups. They work well, that is, in the daytime.

Then comes the damning sentence: “However, when the researchers looked only at pedestrian crashes that occurred at night on roads without streetlights, there was no difference in crash risk for vehicles with and without pedestrian AEB.”

The conclusion comes from the Insurance Institute for Highway Safety (IIHS) in a new report. The group plans to launch a new round of testing to improve the auto industry’s approach to preventing pedestrian crashes.

About the IIHS

The IIIHS is one of the most important forces shaping car safety systems. It’s a research lab funded by a consortium of insurance companies, which have obvious reasons for wanting to prevent car crashes.

The institute operates what may be the world’s most rigorous crash testing program and gives awards to cars that do well in its safety tests. Automakers covet the institute’s Top Safety Pick award. In recent years, they’ve been earning the award with regularity. Two automakers – Volvo and Genesis – even won the award with every single vehicle they built last year.

The IIHS has begun introducing harder tests to try to raise the bar.

Examining Automated Systems

Lately, IIHS has turned its attention to automated safety systems. It helped negotiate a commitment from automakers to add AEB systems to most cars and has been calling out those that drag their feet.

Last month, it released findings suggesting that driver aids like lane-centering assist and adaptive cruise control don’t actually do much to make driving safer. It announced plans to rate cars based on how well their attention monitors – the things that make sure you’re not depending on driver aids too much – detect and alert distracted drivers.

Now, the IIHS is taking a closer look at emergency braking.

Examining Real Crashes

First, the institute examined data from real-world accidents to see what impact the systems have had. They compared crash rates between identical vehicles with and without AEB systems. Accounting for factors like the quality of headlights and driver age, they found that AEB systems reduced crashes. AEB-equipped cars showed a 27% reduction in pedestrian crash rates of all severities and a 30% reduction in injury crash rates.

But, when they examined lighting conditions, “a more complex picture emerged.” AEB reduced crash rates by 32% in daylight and 33% in areas with artificial lighting at dawn and dusk. But the systems made no difference at all in nighttime crashes. Since, the IIHS says 75% of fatal pedestrian crashes happen at night, that’s a critical blind spot.

They also made no difference on roads with speed limits over 50 mph or in crashes where the vehicle was turning.

Practical Testing

IIHS researchers then performed some testing of their own.

They’ve tested AEB systems in daylight for several years. This time, they ran the same test in the dark with small SUVs from eight manufacturers. They tested each once with the headlights on the low-beam setting and once on the high-beam.

The result?

“Today’s pedestrian AEB systems don’t work as well in the dark as they do in daylight,” the Institute says. The best performers (the Ford Bronco Sport and Toyota C-HR) used a combination of cameras and radar (which does not depend on lighting). The one radar-only system tested (the Volkswagen Taos) did the best at night but the worst in daylight.

The institute plans to develop a more formal nighttime test and run it on every AEB-equipped car. Researchers expect to publish their first round of ratings later this year.

“The daylight test has helped drive the adoption of this technology,” says David Aylor, manager of active safety testing at IIHS. “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.