Reflective clothing could make you invisible to car safety systems at night

• Reflective clothing might not help in all situations at night
• Electronic safety systems in vehicles don’t see the same way as the human eye
• New federal safety regulations go into effect in 2029

Reflective clothing makes pedestrians more visible to human drivers, but it could make them invisible to the automatic emergency braking (AEB) systems meant to lessen the likelihood of vehicle-pedestrian collisions, according to a new IIHS case study.

“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,” study author David Kidd said in a statement. “Unfortunately, the moving strips didn’t have the same effect for the pedestrian AEB systems we tested and probably confounded their sensors.”

The insurance-industry-backed nonprofit previously found that now-common automatic emergency braking systems reduce the rate of pedestrian fatalities by 27% overall, but that at night their effect is negligible. To better account for this, current IIHS safety ratings now emphasize nighttime performance of these systems.

But, digging further for root causes of the disparity, researchers looked specifically at the effect of conspicuous clothing and increased roadway lighting on the performance of automatic emergency braking systems in a 2023 Honda CR-V, Mazda CX-5, and Subaru Forester. The Subaru earned the highest “Superior” rating when it was tested prior to the 2024 rules revamp, the CR-V earned an “Advanced” rating, and the Mazda was not rated.

The standard IIHS pedestrian emergency-braking test uses child and adult dummies dressed in black shirts and blue pants. For this test, researchers used adult dummies with a black sweatshirt and pants, the same outfit with added reflective strips (similar to those used by road workers) on the dummy’s limbs and joints, a retroreflective jacket with black sweatpants, and a white sweatshirt and pants.

Tests were run with different levels of illumination, including no lighting at all, at 25 mph. The CR-V and CX-5 hit the dummy in 84% and 88% of the tests, respectively. The Forester managed to avoid a collision in all but one test.

The CR-V and CX-5 also didn’t slow at all in tests where the dummy was clad in reflective strips. That was also how the dummy was dressed in the one test where the Forester failed to avoid a collision. In that test, the roadway was illuminated at 10 lux—half the federally-recommended level—and the Forester still slowed by more than 80%.

It’s unclear why the Honda and Mazda systems were flummoxed by reflective clothing, and if other automakers’ systems have similar issues, the IIHS concluded, adding that further research is needed. Such research is especially urgent given the spike in pedestrian deaths on U.S. roads in recent years.

The IIHS in 2024 also found that the performance of automatic emergency braking varies from model to model based on other factors like speed. New federal regulations, slated to go into effect in 2029, could help address this by setting minimum performance standards for these systems.