Radar car collision prevention systems put to the test

Matthew Avery, Thatcham Research Manager said: “They will make a major impact on the number of slow speed accidents – in Britain and across the World. Thatcham believes that if manufacturers embrace the new systems and fit them as standard – more than 125,000 injuries will be prevented each year in Britain alone.”

The Volvo City Safety uses laser radar, or LIDAR, to track the distance and speed of the car in front of the driver. The windscreen mounted device renews its calculations 50 times a second, pre-charging the brakes to avoid potential collisions before drivers can even sense the danger.

The system is active at speeds of up to 18.7 mph and has a range of up to six meters in front of the car. If a driver fails to activate the brakes before an imminent collision, the City Safety system automatically stops the car, and even steers it out of harms way. If the failsafe activates while the car is traveling below 10 mph, the collision should be averted completely, and at a speed of below 20 mph, the impact will be reduced by 50%.

The Volvo City Safety will be fitted as standard to the XC60, which is available this November.

Like the City Safety, the Mercedes Distronic Plus uses a form of radar to maintain safe distance from neighbouring cars. However, the two radars on the Distronic Plus are linked to the car’s cruise control, adding an extra level of autonomy to the system. The Distronic Plus operates at speeds of up to 200 km/h, keeping your car in sync with traffic whether it be stop-and-start gridlock or long stretches of freeway.

The short-range 24 gigahertz radar sweeps a fan-shaped 80-degree pattern with 30 meters of range, while the 77 gigahertz radar sweeps a nine-degree pattern at a far longer range – combined, the radars cover 145 meters of road.

As an added safety precautions, the Distronic Plus incorporates the Brake Assist Plus, and the PRE-SAFE system.

The Brake Assist Plus functions in a similar way to the City Safety, monitoring the distance between cars and adjusting brake pressure to avoid collisions. In tests conducted by Mercedes, the integrated system reduced rear collisions in heavy city traffic by 75%.

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