ADAC Test Finds Emergency Braking Systems Fail in Adverse Weather
ADAC tested emergency braking systems in six vehicles under heavy rain, fog, and glare conditions in a controlled weather chamber. All systems failed to perform reliably; the BYD Seal showed the worst results and did not warn drivers when functions became impaired, while the Mercedes CLA performed best but still experienced occasional failures.
What happened
ADAC tested emergency braking and obstacle detection systems in six vehicles under adverse weather conditions using a controlled weather chamber at AVL in Roding. Vehicles travelled at 30 km/h and were required to automatically detect and brake before stationary and moving obstacles under simulated heavy rain, fog with visibility below 20 meters, and glare from low-angle sunlight.
Reported impact
All six systems failed to perform flawlessly across all test scenarios. The BYD Seal showed the worst performance with detection rates of 38 percent and failed to warn drivers when functions became impaired in poor visibility conditions. The Mercedes CLA performed best at 92 percent obstacle detection, but in one scenario initiated braking for a pedestrian and then aborted it without apparent reason.
Index analysis
The test revealed that sensor quantity does not guarantee performance: the Nio EL6, equipped with radar, lidar, and camera, detected obstacles at only 88 percent overall and showed inadequate responses in dense fog despite having multiple sensor types. Tesla's camera-only system achieved 78 percent detection and showed 'surprisingly positive' results in rain and light fog, though it failed to initiate emergency braking in more challenging conditions. Performance rankings were Mercedes CLA 92 percent, Nio EL6 88 percent, Tesla Model Y 78 percent, Subaru Impreza 77 percent, Volkswagen T-Roc 65 percent, and BYD Seal 38 percent.
Classification
Sources and evidence
This record was researched and written by the Index, based on the following original reporting.