Nissan announced Wednesday the newest development under its "Safety Shield" accident prevention program - an electronic system that helps drivers control the distance between their car and the vehicle in front.

The system uses a front bumper-mounted radar sensor to determine the following distance and the relative speed of both cars. If the driver releases the gas pedal the system automatically applies the brakes. If the system itself determines that braking is required (presumably because the vehicle ahead is slowing), the driver is alerted by a lighted indicator and a buzzer, and the gas pedal automatically moves upward to "assist the driver in switching to the brakes."

Nissan expects the system to be particularly useful in heavy traffic, when frequent braking is required. No word on when (or if) the system will see production.