To avoid tailgating, one should follow the

Most rear-end collisions are caused by tailgating. To avoid tailgating, use the "three-second rule": When the vehicle ahead of you passes a certain fixed point, such as a sign, it should take your vehicle about three seconds to reach that same point. To count three seconds, count "one-thousand-one, one-thousand-two, one-thousand-three." [Do Not Be a Tailgater!; Know What is Ahead; Visual Search; California Driver Handbook]