Mercedes-Benz Pre-Safe Braking System World Premiere

Press Release

Field trials and testing in the simulator: One million test kilometres on the road and two years in the laboratory

• Over 500 drivers test the system in Germany and the USA
• Cutting-edge test facility simulates critical on-road situations in real time
• 70 participants take part in a series of tests in the simulator

The new radar-based safety systems for the S-Class have completed an unprecedented test programme. Mercedes-Benz has a total of 30 test cars in operation in Germany and the USA, helping to assess the technology in everyday traffic. To date over 500 drivers have cover around one million kilometres in these field trials. Cameras and computers on board the test cars log critical traffic situations and enable precise analysis of how reliably the systems work and how they support the drivers.

In the laboratory the cutting-edge “hardware in the loop” test procedure combines the advantages of field trials with those of computer simulation. Brake Assist PLUS and the PRE-SAFE® brake have completed intensive endurance tests on the test rig – in a virtual world but using data from real traffic situations. The method allows the hardware intended for use in series-produced vehicles, in other words the system components such as control units, hydraulic units and sensors, to be included in the test runs. Powerful computers feed the units with sensor data from simulated traffic situations and log the control commands with which the components respond.

This allows the control electronics of the PRE-SAFE® brake to be confronted with thousands of real traffic situations over a short period of time and, proving their reliability in the process.

As they progress towards use in series-produced vehicles, Mercedes safety systems regularly undergo an extensive test programme on the DaimlerChrysler Research simulator in Berlin. The new PRE-SAFE® brake was tested by 70 drivers here over the course of four weeks. They drove along a virtual road with queues of traffic at around 80 km/h.

After some time, the site of an accident appeared on the left-hand side of the road. The cars involved, people on the road and a police car briefly distracted the test drivers, and at this precise moment the car in front braked – at first gently, but then suddenly will full braking force. The S-Class drivers were immediately given visual and audible warnings.

Operation and function in detail: How the new PRE-SAFE® brake works

Operating concept:
The system is activated at the touch of a button on the multifunction steering wheel and details appear in the central instrument cluster display. The “PRE-SAFE® brake” menu item is part of the “Assistance” control area.

Whenever proximity control – and hence the PRE-SAFE® brake – is active, a permanent symbol appears in the instrument cluster.

Range:
The PRE-SAFE® brake is active in the speed range between 30 and 180 km/h, provided vehicles have been registered up ahead. The system also reacts when approaching a stationary queue of traffic, as long as the S-Class is not travelling at over 70 km/h. Cars coming in the opposite direction, sudden obstacles or other vehicles which appear, for example, in the side of the radar area at junctions are ignored. The system is not available where the radar signals encounter objects made from materials with a poor reflective quality or where the sensors are impaired by external factors such as dirt or snow.

Warnings:
If the gap between the car and the vehicle in front becomes too small, a red warning triangle appears in the tachometer. If there is a danger of an accident, an addi-tional warning tone is sounded. Once three warning tones have been emitted (approx. 1.6 seconds before the calculated impact), the PRE-SAFE® brake automatically intervenes and begins autonomous partial braking, unless the driver has already reacted. Pre-emptive protective measures in the interior are also activated.