Putting a big SUV in reverse is the first step in many a car accident. Infiniti’s Back-Up Collision Intervention, available on the JX 35 SUV, will stop the vehicle if it anticipates an impact with a moving or stationary object. When the driver shifts into reverse, radar and sonar sensors scan behind the car; flashing lights mounted next to the side-view mirrors indicate the presence of an obstacle. Ignore that message and the car automatically brakes.