Automatic Braking

Systems to automatically brake a vehicle if it is about to slam into the car in front at low speeds are preventing one out of four rear-end collisions, the Highway Loss Data Institute reports.

The study, however, covers just one vehicle equipped with such a system: the Volvo XC60 midsize crossover SUV.

The study of insurance claims found that Volvo XC60 outfitted with a standard collision avoidance feature called City Safety are 27% less likely to be involved in low-speed crashes than comparable vehicles without the system. The study looked at property damage liability coverage — the insurance that pays for damage to vehicles that an at-fault driver hits.

"This is our first real-world look at an advanced crash-avoidance technology, and the findings are encouraging," says Adrian Lund, president of HLDI. "City Safety is helping XC60 drivers avoid the kinds of front-to-rear, low-speed crashes that frequently happen on congested roads."

Volvo and other automakers also offer optional forward-collision-warning systems designed to help drivers avoid crashes at higher speeds, but there's no word on their effectiveness yet under the same study procedure.

The City Safety system became standard on XC60s starting last model year. It also is standard on 2011-12 S60 sedans and 2012 model S80 sedans and XC70 wagons.

City Safety uses an infrared laser sensor built into the windshield and works at speeds of about 2 to 19 miles per hour. It detects and reacts to other vehicles within 18 feet of the XC60's front bumper during both daytime and nighttime driving.