The S550 can detect pedestrians in front of the car by analyzing data from the stereo camera and radar. If a pedestrian is in danger, the driver is warned, and brake assist is provided as necessary. If the driver fails to brake, the computer takes over and brings the vehicle to a halt. The same speed thresholds for crash prevention and mitigation apply.

The system distinguishes between a pedestrian and, for example, a stop sign or a tree bending in the wind, using complex algorithms to analyze data from the sensors, Mercedes says.

Stuart Klapper, a managing director at Autoliv, which provides radar and camera components to automakers, said in a telephone interview that his company spent $50 million developing algorithms for pedestrian recognition.

“You have to have a lot of confidence that it’s truly a pedestrian,” he added.