Brake expectations

Japanese car manufacturer Honda has launched the Collision Mitigation Brake System, a vehicle collision-avoidance system that predicts crashes and automatically assists with braking.

Japanese car manufacturer Honda has launched a vehicle collision-avoidance system that predicts crashes and automatically assists with braking.

The radar-based Collision Mitigation Brake System (CMS) predicts rear-end collisions based on driving conditions, distance to the vehicle ahead and relative speeds.

Some luxury cars such as Jaguars already have adaptive cruise control systems, in which radar monitors the distance from the vehicle ahead and intervenes to slow the car if it gets too close.

However, the Honda system can assess the likelihood of an accident, using data from sensors that detect factors such as yaw, steering angle, wheel speed and brake pressure to calculate the distance between cars, relative speeds and the anticipated vehicle path.

Visual and audio warnings are used to prompt the driver to take preventive action, but the system can also initiate braking if the warnings are ignored.CMS will be available on new versions of Honda’s Inspire sedan sold in Japan from June, and will be coupled with the manufacturer’s E-Pretensioner system, which retracts the seatbelt during sharp braking or in anticipation of an accident. It could be available in the UK on Japanese-built models of the Accord in as little as two to three years, the manufacturer said.

‘This goes beyond other safety systems,’ said Honda spokesman Lawrence Pearce. ‘It can recognise when an accident is about to happen and can do something about it, unlike systems that just prepare drivers for an impact by taking action such as tightening their seatbelts. Globally, the potential for saving lives is huge.’

CMS uses a millimetre-wave radar system to detect vehicles in front to a distance of 100m in a 16-degree arc. This is combined with information from other sensors to predict whether a crash is likely.

If so, the CMS sounds an alarm and displays the message ‘brake’ on the display panel. If the distance between cars continues to narrow, CMS applies light braking and tightens the seatbelt gently several times, alerting the driver with a tactile warning.

Once the driver is braking CMS will apply additional pressure if it calculates that the pedal is receiving insufficient pressure to avert the crash.

However, if the crash is seen as unavoidable, the seatbelt is tightened in anticipation and the system applies the brake with force.

The system has been designed as a successor to Honda’s intelligent driving system (HIDS), launched in Japan in 1997 as a form of adaptive cruise control.This can reduce speed using throttle control or apply the brakes to restore a safe distance between vehicles, but cannot anticipate a crash.

CMS will also include HIDS’ Lane Keeping Assist System, consisting of a digital camera mounted in the car’s mirror that can recognise road markings and keep the driver in the centre of its lane. The device can make steering corrections to keep the car on target and activates an alarm warning when the driver strays.

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