USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

CMV Driving Tips - Following Too Closely

Following too closely may be defined as, “situations in which one vehicle is following another vehicle so closely that even if the following driver is attentive to the actions of the vehicle ahead he/she could not avoid a collision in the circumstance when the driver in front brakes suddenly."14

In addition to providing enough stopping time, proper following distance allows for more time to make good, well-planned decisions and affords other drivers the opportunity to scan the sides, look far enough ahead, and view the vehicle immediately in front.

The Large Truck Crash Causation Study (LTCCS) reported that 5 percent of truck crashes occurred when the Commercial Motor Vehicle (CMV) driver was following the lead vehicle too closely.15

Below are some tips that will help you maintain the correct following distance during various driving conditions.

TIP #1: Maintain a Safe Following Distance

Large trucks need additional space between vehicles to allow for safe braking and unexpected actions. In crashes, large trucks most often hit the vehicle in front of them.16

Did You Know? If you are driving below 40 mph, you should leave at least one second for every 10 feet of vehicle length. For a typical tractor-trailer, this results in 4 seconds between you and the leading vehicle. For speeds over 40 mph, you should leave one additional second.16

Did You Know? On October 15, 2007, as cars began to slow for construction in the left lane, a CMV driver failed to brake and crashed into the vehicle ahead of him, killing a 47-year-old woman. The crash also involved two other vehicles and shut down the roadway for 5 hours. The CMV driver was charged with misconduct with a motor vehicle, and following too closely.77

An example of a driver following too closely is shown in the video clip below. Training exercise questions follow the video clip.

VIDEO DESCRIPTION: The CMV driver is traveling in the far right lane of a three-lane highway during the day. There is an exit-only lane on the right, adjacent to the driver's lane. The driver is following a lead passenger vehicle closely. The passenger vehicle begins to slow in order to move to the left and into the middle lane. The CMV driver does not slow down appropriately and comes close to the rear of the passenger vehicle as it changes lanes.

TRAINING EXERCISE: After viewing the video, try to answer the following questions:

  • Does the driver appear to adjust his vehicle's speed to maintain a safe following distance with the lead vehicle?
  • Why was the lead vehicle slowing down?
  • Why did the driver brake excessively?
  • What could the driver have done differently?

TIP #2: Double Your Following Distance in Adverse Conditions

Adjust your following distance to appropriately match weather conditions, road conditions, visibility, and traffic. In emergency conditions, maintaining a safe distance from the vehicle in front of you will allow you to stop safely and/or to take necessary evasive action.78

Did You Know? The average stopping distance for a loaded tractor-trailer traveling at 55 mph (in ideal conditions) is 196 feet, compared with 133 feet for a passenger vehicle.79

Did You Know? Braking distance can be greatly affected by road surfaces, weather conditions such as rain, ice, and snow, or debris.78