Reflectors confuse automatic emergency braking systems as five of six models struggle

Six cars, one unexpected problem

ADAC’s study involved the Tesla Model Y, BYD Seal, Hyundai Tucson, Dacia Duster, Opel Astra and Mercedes-Benz CLA.

First, the testers established the speed at which each car’s automatic emergency braking system could avoid a collision with a pedestrian in the dark. They then repeated the tests with dummies wearing different clothing.

All six cars successfully detected an adult wearing a standard high-visibility vest. However, the situation changed significantly when the dummy wore standard workwear with reflective strips of the kind worn by emergency responders, road workers or police officers. Almost all the cars reacted too late or failed to brake.

The test involving children was even more concerning. All the cars could detect a child in dark clothing, but most systems struggled with a child wearing a reflective jacket and carrying a school bag with reflectors.

The Mercedes-Benz CLA was the only car able to detect a child wearing reflectors stepping into the road from behind a parked car. However, even the Mercedes had difficulty recognising the adult in workwear.

The problem may lie in the software, not the cameras

The result is technically revealing. Reflectors make pedestrians more visible to the human eye, but a car’s electronics must not only see an object but also understand what it is.

An automatic emergency braking system uses information gathered by cameras and, depending on the model, radar. Software analyses objects’ shape, movement and position, then decides whether braking is needed to avoid a collision.

Highly reflective surfaces can alter a pedestrian’s image so much that the software can no longer classify them correctly.

ADAC believes the shortcoming may lie primarily in object-recognition algorithms, meaning manufacturers could address it in many cases with a software update.

This is not merely a theoretical problem. A study published in 2025 by the US Insurance Institute for Highway Safety (IIHS) found similar shortcomings in the automatic emergency braking systems of the Honda CR-V and Mazda CX-5. The Subaru Forester performed considerably better in those tests.

A gap in Euro NCAP testing

ADAC’s study also exposes a weakness in European vehicle safety assessment.

Euro NCAP checks how emergency braking systems perform in scenarios involving pedestrians, including in the dark. However, the effects of reflective workwear and children’s reflective accessories are not part of the standard test protocols.

As a result, a car can achieve a high safety rating yet struggle when a pedestrian is wearing entirely ordinary safety equipment.

The issue is relevant wherever wearing a reflector is an everyday safety measure in the dark. It particularly affects children and road workers, whose clothing has reflective strips at different heights.

However, the test results do not provide grounds to claim that all emergency braking systems are equally flawed. ADAC used a different reference speed for each model, so the results are not directly comparable.

Abandoning reflectors would be the wrong conclusion

ADAC stresses that the study provides no reason to stop using reflectors.

A reflector helps a driver notice a pedestrian earlier, and its safety benefits outweigh the potential risk arising from shortcomings in electronic driver assistance systems.

The real problem lies in car manufacturers’ software. An emergency braking system must be able to recognise a pedestrian regardless of whether they are wearing a dark jacket, a high-visibility vest or workwear with reflective strips.

The study shows that even modern active safety technology is not yet reliable enough in all real-world traffic conditions. A driver assistance system may prevent an accident, but it cannot be relied on blindly.

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