The expected popularity of anticipatory assistance systems demands that future testing procedures will have to make allowances for the effect of preventive protection system, BMW argues. In what the car vendor calls a world premiere, a vehicle equipped with a functional radar-based anticipatory drives assistance system successfully passed a crash test involving brake intervention.

The anticipatory assistance system involved was combined with Active Cruise Control, activating an alarm scenario in two stages.

In the event of a potential collision with the vehicle in front, the driver is first given a preliminary warning by means of an illuminated red vehicle symbol on the instrument panel and on the Head-up Display. At the same time, the braking system is prefilled and the minimum triggering level of the hydraulic brake assistant lowered. This ensures that in an emergency brake pressure is built up faster when the driver applies the brakes, therefore significantly reducing the stopping distance.  

If the danger of collision is acutely imminent, the second stage of the collision warning commences. In situations demanding particularly rapid intervention by the driver, the system activates an acoustic signal in addition to the visual warning. Should the driver still not react to the request to apply the brakes, a time-limited delay procedure is activated: The car brakes for 1.2 seconds with reduced deceleration, whereby speed is already reduced before the driver can apply the pre-tensioned brakes. 

In the case a collision cannot be avoided, an automatically activated emergency brake application function ensures that collision speed is, significantly reduced.

Based on a conventional EuroNCAP test with the car approaching an offset obstacle at 64 km/h, a so-called offset crash, the vehicle used in the test incorporating advanced brake intervention likewise initially accelerated to 64 km/h. However, the automatic hard brake triggered by the system reduced the collision speed to just 40 km/h.

The most significant result of the crash test: In the event of a crash incorporating prior brake application, the severity of impact is reduced considerably, thereby significantly lessening the strain on the occupants.

Another relevant finding is that due to full brake application immediately prior to impact and the car's pitching movement resulting from this, the vehicle changes its position, particularly when the front bumper hits the block. The vehicle collides with the obstacle in a slightly “lower” position than in the case of a crash occurring without prior application of the brakes. This could play a role in the body design of future cars.

Previous testing facilities have not permitted verification of the effect of anticipatory occupant protection systems in crash tests. The demonstrative test implemented by BMW in collaboration with Dekra is the first step in testing future pre-crash scenarios, the car vendor said.

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