High-Visibility Clothes Are ‘Invisible’ to Autobrake Systems, Says IIHS

Modern cars have all kinds of safety tech, but new research from the Insurance Institute for Highway Safety (IIHS) reminds us it’s not foolproof. Taking a closer look at the performance of automatic emergency braking systems at night, a surprising anomaly surfaced. It seems some systems can’t detect pedestrians wearing clothing specifically designed to make them visible in darkness.

The study involved three test vehicles: a Honda CR-V, Mazda CX-5, and a Subaru Forester, all from the 2023 model year. The plan was to evaluate the effectiveness of autobrake systems with pedestrians at night, using different lighting conditions and types of clothing. According to the IIHS, such systems generally reduce vehicle/pedestrian collisions by 27 percent overall. But that largely applies to daylight scenarios. At night, IIHS claims the difference is negligible. Unfortunately, that’s when most pedestrian incidents occur.

Running at a constant 25 mph, the Honda and Mazda struck a vast majority of pedestrian dummies regardless of the clothing they wore. With reflective stripes added, both SUVs plowed into them. By contrast, both vehicles at least slowed when a dummy was wearing black clothing—the opposite of what you’d expect, at least from our human perspective.

It’s important to note that different lighting scenarios created different results. For example, The CX-5 slowed much more with 10 lux of extra lighting in the area. Bumped to 20 lux, however, it did much worse. Meanwhile, the Subaru did far better. It avoided hitting the pedestrian dummies in all but one test. Ironically, the one failure occurred with a dummy wearing reflective clothing.

The IIHS could only speculate why these systems struggle with bright clothing.

“The placement and motion of reflective strips on the joints and limbs of pants and jackets allows drivers to quickly recognize the pattern of movement as a person,” said David Kidd, a senior research scientist at IIHS. “Unfortunately, the moving strips didn’t have the same effect for the pedestrian AEB systems we tested and probably confounded their sensors.”

The full case study on nighttime autobrake systems with regard to lighting and clothing is available on the IIHS website.