WASHINGTON (AP) — As a safety demonstration, it was a heart-stopper: A Ford Taurus was seconds away from cruising through an intersection when suddenly a row of red lights pulsed on the lower windshield and a warning blared that another car was approaching fast on the cross street.

Braking quickly, the driver stopped just as the second car, previously unseen behind a large parked truck, barreled through a red light and across the Ford’s path.