Still in the pre-production stage, the system uses a pair of cameras to provide a stereo image to the computer that can then use it to judge distance, in much the same way humans do. However, because it is computer-based, it can make much quicker and more fine-grained comparisons that the human eye and brain are capable of. One example where the system has an advantage over humans is the case of the cyclist that is drifting almost imperceptibly into the lane. The system can see this and warn in advance, while it might be too late to react once the cyclist moves into the driver's field of view.
The technology is much like BMW's system debuted recently on the 7-series, though that technology relies instead on a single night-vision capable camera to extend visibility in low-light conditions. The image-processing software performs a similar function in both cases, but Mercedes-Benz claims their stereoscopic solution is unique.
Once the system detects a collision course between the car and any object or an unnoticed red light or stop sign, it flashes a visual warning. If the driver does not respond, it then sounds an audible warning as well. If the driver still does not respond, the car will briefly and abruptly brake the car to get the driver's attention.
Such technology usually makes its way into the S-Class of cars first amongst Mercedes' lineup, trickling outward through the other models from there. It's not yet known when, or if, this system will go into production, however.