Ask a Trooper: What is a safe following distance on the road?

Published 7:32 pm Wednesday, December 18, 2019

Ask a Trooper by Troy Christianson

Troy Christianson


Question:  What is the legal following distance? What can I do when someone is following too close behind me? Isn’t there a rule of so many vehicle lengths for miles per hour to use as a guide?

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Answer: The only law regarding following distance pertains to vehicles pulling trailers. This includes trucks as well as semi-truck tractors with trailers. They must maintain a minimum distance of 500 feet.

While state law does not require a specific distance for vehicles not pulling trailers, it does say that you shall not follow another vehicle more closely than is reasonable and prudent, having due regard for the speed of such vehicles and the traffic upon and the conditions of the highway.

We recommend what’s called the three-seconds-plus following distance rule. Watch the vehicle in front of you. When that vehicle gets past an object such as a sign, pole, bridge, etc., then count off three seconds. You should not arrive at that spot sooner than your count to three. If you do, then you are following too close.  Also, you must add one second for every hazard that exists.  Hazards include but are not limited to heavy traffic, rain, snow, fog, driving into the sun, etc. In some cases you might have to allow six, seven seconds (or even more) to be safe because of existing hazards.

Learn how to recognize any kind of hazard while you are driving out there, and practice the three-second (plus) following rule.  If everyone were to follow this simple rule, many crashes that cause serious injuries and or death could be prevented. 

Check your mirrors every three to five seconds so you know what is going on around you. While we cannot control the vehicles around us, we can control our own driving habits.    

You can avoid a ticket — and a crash — if you simply buckle up, drive at safe speeds, pay attention and always drive sober.  Help us drive Minnesota toward zero deaths.

If you have any questions concerning traffic-related laws or issues in Minnesota, send your questions to Sgt. Troy Christianson, Minnesota State Patrol, at 2900 48th St. NW, Rochester, MN 55901-5848; or reach him at

Troy Christianson is a sergeant with the Minnesota State Patrol.