High-visibility (hi-vis) clothing is a crucial safety measure for pedestrians, cyclists, and road workers in the UK.

The reflective garments or clothing additions help reduce accidents by making individuals more visible to drivers.

However, while vehicles deploy more and more technology to aid drivers in road safety situations, the hi-vis clothing could be undermining their effectiveness.

Wood for the trees

A recent study by the Insurance Institute for Highway Safety (IIHS) in the US suggests that while high-visibility garments enhance visibility for human drivers, they may actually impair the effectiveness of automated pedestrian crash prevention systems.

The study tested pedestrian automatic emergency braking (AEB) systems in three 2023 vehicle models—Honda CR-V, Mazda CX-5, and Subaru Forester—under different lighting conditions and with test dummies wearing various types of clothing, including black, white, and hi-vis reflective gear.

Surprisingly, while the Subaru Forester performed well in nearly all conditions, the Honda CR-V and Mazda CX-5 struggled to detect dummies dressed in reflective clothing.

When the test dummy wore black clothing with retroreflective strips designed to mimic safety gear, the CR-V and CX-5 failed to slow down in 100% of the test runs.

This suggests that certain pedestrian AEB systems may not be optimised to recognize reflective materials, potentially putting road workers and cyclists at risk.

Road safety visibility

In the UK, high-visibility clothing is widely recommended to improve road safety.

According to the Department for Transport (DfT), 75% of fatal pedestrian accidents occur at night, when visibility is lower.

Hi-vis garments with reflective strips can increase a pedestrian’s visibility distance by up to 300 meters, giving drivers more time to react.

A study by the Royal Society for the Prevention of Accidents (RoSPA) found that wearing reflective clothing at night reduces the risk of being hit by a vehicle by up to 85%.

Additionally, research indicates that cyclists wearing hi-vis gear are 37% less likely to be involved in a collision compared to those without it.

Analogue Vs digital

While hi-vis clothing plays a critical role in reducing road accidents, the IIHS study highlights a potential flaw in modern crash avoidance technology.

Many automated systems rely on sensors and cameras that may not accurately interpret reflective clothing, potentially mistaking it for background light or failing to register it as a pedestrian.

David Harkey, President of the IIHS, emphasized the importance of addressing this issue: “It’s untenable that the clothes pedestrians, cyclists, and roadway workers wear to stay safe may make them harder for crash avoidance technology to recognise.”

With pedestrian AEB systems reducing crash rates by 27% overall but struggling in low-light conditions, manufacturers must refine their technology to ensure it complements, rather than contradicts, traditional road safety measures.

Testing fashion

For the study, researchers conducted multiple trials with an adult-sized dummy clothed in a black sweatshirt and trousers, a reflective jacket with black trousers, the black sweatshirt and trousers with retroreflective strips added on the dummy’s limbs and joints, as well as a white sweatshirt and matching trousers.

The retroreflective strip pattern used was similar to the one seen on roadway worker outfits, although their safety gear is generally bright orange or yellow rather than black.

Multiple tests were carried out with the cars travelling at 25 mph with no roadway lighting, 10 lux of illumination in the crosswalk, or the standard US 20 lux of illumination in the crosswalk.

The dummy crossed the track perpendicular to the path of the vehicle in all scenarios.

The CR-V and CX-5 hit the dummy in 84% and 88% of the test runs, respectively, while the Forester avoided a collision in all but one trial.

Neither the CR-V nor CX-5 slowed at all when the dummy was wearing clothing with reflective strips that articulated its limbs.

Otherwise, the performance of the Honda and Mazda crash avoidance systems varied.

When the dummy was dressed in black, both vehicles slowed substantially when using their high beams — a test that was only conducted with no roadway illumination.

Using their low beams in those same conditions, the CR-V failed to slow at all and the CX-5 reduced its speed by less than a third.

Both vehicles did much better with 20 lux of additional light.

Not so bright

The vehicles were only tested using their low beams for all the other types of clothing.

When the dummy was dressed in the reflective jacket, the CR-V didn’t slow in any of the trials, regardless of additional roadway lighting.

In contrast, with no roadway illumination and with 10 lux of added light, the CX-5 slowed much more than it did when the dummy was clad in black.

However, with 20 lux of added light, it performed worse with the dummy in the reflective jacket than when it wore the black outfit.

When the dummy was dressed in white, the CR-V didn’t slow at all with no added roadway illumination but notched up its best performances with 10 and 20 lux of added light.

However, it did better with 10 lux of illumination than with 20 lux.

The CX-5 performed better than it did with the dummy in black but not as well as the dummy wearing the reflective jacket.

It also slowed less with increased roadway illumination when the dummy wore white.

In contrast to the two other vehicles, the Subaru came to a complete stop without hitting the pedestrian dummy in every trial except one run in which the dummy was wearing clothing with reflective strips and the roadway was illuminated to 10 lux.

Even in that run, it slowed by more than 80%.

“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 study author 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.”

Conclusion

Hi-vis clothing remains an essential tool for pedestrian safety, significantly reducing accident risks on UK roads.

However, as automated safety features become more common, the research concludes that vehicle manufacturers must enhance their pedestrian detection systems to properly recognise all forms of protective clothing, including reflective gear.

The authors are calling for further research and improvements ‘to close this critical gap in road safety technology’.

By addressing these issues, we can ensure that both human drivers and automated systems work together to protect vulnerable road users, making roads safer for everyone.