High-Visibility Clothing Could Make Pedestrians Invisible to Self-Driving Cars: IIHS

Automatic emergency braking systems may not be as effective when pedestrians are wearing reflective clothing on dark roads.

A new study suggests that light-colored, reflective clothing designed to help pedestrians stand out to human drivers may actually render them less visible to automated crash prevention systems.

Previous studies have found that pedestrian automatic emergency braking (AEB) systems can reduce pedestrian crash rates by 27%. However, most fatal pedestrian accidents occur at night, where AEB systems are far less effective on dark roads. New research may now explain the reason behind this diminished performance.

Despite pedestrians’ efforts to stay visible and safe, a new report from the Insurance Institute for Highway Safety (IIHS) reveals that wearing white or reflective clothing could unintentionally increase their vulnerability to faulty AEB systems, underscoring the need for automakers to improve nighttime AEB performance.

In the study, IIHS researchers David Kidd and Watson Spivey evaluated how clothing and better roadway lighting impact AEB system performance for pedestrians.

Researchers conducted 167 trials to analyze the performance of AEB systems in three 2023 small SUV models. They tested the systems using adult-sized dummies dressed in various outfits: black sweatshirts and pants, reflective jackets with black sweatpants, black clothing with reflective strips on the limbs, and white sweatshirts and pants, under varying lighting conditions.

Findings revealed that the Honda CR-V and Mazda CX-5 vehicles hit the dummy in 84% and 88% of the test runs, respectively, with neither slowing when the dummy was wearing clothing with reflective strips.

The Subaru Forester avoided a collision in all trials except when the dummy wore reflective strips in 10 lux illumination, a lighting level equivalent to dim street lighting

In the trials, when the dummy was dressed in all black, the Honda and Mazda vehicles slowed substantially when using high beams. However, when using low beams, they either failed to slow at all or reduced their speed by less than a third, respectively.

The CR-V showed no slowing at all when the dummy wore the reflective jacket, regardless of the roadway lighting. In contrast, the CX-5 slowed more at 10 lux when the dummy was dressed in all black compared to the reflective jacket, but it slowed less at 20 lux.

In the trials where the dummy wore all white, the CR-V didn’t slow at all with no added roadway illumination and the CR-X performed better than when the dummy was dressed in all black, but not as well as when the dummy wore the reflective jacket.

The findings suggest the placement and motion of reflective strips on the limbs of jackets and pants of pedestrians help drivers quickly recognize the pattern of movement as a person, but do not have the same effect for AEB systems.

Researchers are unsure as to why the Honda and Mazda systems struggled with the reflective strips, or how many other systems may have trouble identifying pedestrians in certain clothing.

“It’s untenable that the clothes that pedestrians, cyclists, and roadway workers wear to be safe may make them harder for crash avoidance technology to recognize”, said IIHS President, David Harkey.

The study suggests that increasing vehicle lighting may enhance pedestrian automatic braking systems’ effectiveness, but it also emphasizes the need for automakers to improve AEB systems and to further research how crash avoidance systems respond to specific safety equipment used by pedestrians and roadway workers.

Pedestrian Hazards for Self-Driving Cars

As self-driving cars become more prevalent on public roadways, safety features such as automated braking systems are essential for protecting pedestrians. However, numerous issues have surfaced in recent years as a result of these systems failing.

In early October 2024, a Tesla self-driving technology investigation was launched following four pedestrian accidents, including one fatality, involving Tesla vehicles using Full Self-Driving features in areas with reduced roadway visibility, such as conditions caused by sun glare, fog or airborne dust.

Later that same month, Cruise, a General Motors subsidiary, faced a $1.5 million fine after one of its ADS vehicles struck a pedestrian.

As technology continues to advance, enhancing safety features such as recognizing and braking for pedestrians, while also understanding how these features perform in various scenarios, is becoming increasingly crucial to safeguarding lives and reducing accidents.