Following vehicles too closely is the primary cause of rear end crashes. The following guidelines should assist you in maintaining a safe following distance.

The minimum following distance in dry, sunny driving conditions is the “three second plus” rule of thumb1. When the vehicle in front of you passes a stationary object begin counting. At a minimum, you should reach the same object no sooner than three seconds after the vehicle in front of you…four seconds is even better.

Following distances should be increased when road conditions have deteriorated due to the weather. Be aware that even brief rain showers may contribute to slippery road conditions. Bridges and overpasses may become slick in cold weather before other road surfaces. You should also increase following distance when visibility is poor and when you are in traffic where you can anticipate the vehicle in front of you may have reason for sudden stops.

Remember that several factors contribute to stopping distance. These factors include the condition of your vehicle’s tires and brakes and the weight of your vehicle. Poorly maintained vehicles and heavier vehicles require longer stopping distances.

1National Safety Council