Volvo has announced that it is working on a new braking system, called City Safety, that will thwart or reduce rear-end collisions — the most frequent low-speed accidents. It will be available on some of its models within two years.

The system will use an optical radar in the upper windshield to sense the proximity and speed of the car ahead 50 times per second and automatically engage the brakes to reduce the impact of a rear-end collision or avoid one altogether. Drivers will be able to turn the system off with a switch near the steering wheel.

The radar system may not work in fog, mist, heavy ran or snow, said Volvo spokesman James Hope. The company’s next goal is to convince government agencies that the self-braking system is ready for the road. “We are working closely with regulatory agencies in the U.S. to test the safety and efficacy of the City Safety system and hope to implement it in our cars in the next few years,” Hope said.

According to the National Highway Traffic Safety Administration’s website, low-speed rear-end collisions are rarely fatal, but they usually result in auto damage that is not always reported to insurance companies, and are therefore costly to the consumer. Such collisions can often cause medical problems including whiplash, bumps and bruises — not to mention higher insurance rates when the accident is reported.

Volvo is a safety innovator. It was the first manufacturer of passenger cars to employ the now ubiquitous three-point safety belt starting in 1959 and pioneered side-impact protection systems, which it first rolled out in 1991.

Acura offers a Collision Mitigation Braking System on its top RL sedan that senses distance from a vehicle ahead to predict the likelihood of a rear-end collision and uses visual and audible warnings to prompt the driver to take preventative action. Mercedes-Benz offers a similar advanced braking system called Pre-Safe that can also detect an immenent collision, but this device precharges the braking system for a panic stop. Neither the Acura system, nor that of Mercedes-Benz automatically applies the brakes as Volvo's City Safety system does.
Other advanced safety devices just starting to appear on new models include lane departure warning systems, such as on the Infiniti M35 and M45 sedans, and a blind-spot warning system available on the Audi Q7 SUV, among others.