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Stopping Distance: Semi-Trucks vs. Cars

Updated February 23, 2023 | By Wilson Kehoe Winingham staff

Truck drivers and the trucking industry are highly regulated, and for good reason: Semi-trucks and tractor-trailers are so large and heavy that accidents involving them on the roadways often result in fatalities. The size and weight of these trucks also affects their stopping distance—how much space and time they need to come to a complete stop.

When you are driving near a semi-truck, you may hear a hissing sound when it slows or attempts to stop. That sound should serve as a reminder to keep your distance.

Truck Stopping Distance vs. Car Stopping Distance

The time and distance tractor-trailers and other commercial trucks need to come to a complete stop is much greater than that of smaller passenger vehicles, such as cars or pickups.

The Federal Motor Carrier Safety Administration (FMCSA) calculates the stopping distance of semi-trucks vs. cars as follows:

  • A normal passenger vehicle driving at 65 miles per hour will need about 300 feet to stop.
  • A fully loaded commercial truck driving at 65 miles per hour will need about 600 feet to stop.

For a more visual comparison, a car takes about the length of a football field to stop, while a semi-truck needs the distance of approximately two football fields to stop.

Additionally, stopping distance can vary significantly based on road conditions and other factors.

Factors Affecting Semi-Truck Stopping Distance

Many different factors come into play when it comes to the stopping distance of a semi-truck. Reaction time, weight, speed, road conditions, and brake systems all affect a truck driver’s ability to come to a complete stop.

Reaction Time

The time it takes drivers to perceive and react to danger is known as the reaction time. For both passenger vehicle drivers and truck drivers, it usually takes about 1.5 seconds to see a dangerous situation and apply the brakes.

However, since semi-trucks are so tall, truck drivers may be able to see oncoming obstacles from farther away, giving them a slight advantage over shorter cars and pickup trucks.


One of the many reasons semi-trucks take so long to stop is because of their weight. The stopping distance of trucks increases with heavy loads, which cause them to accelerate more quickly when going downhill and take longer to come to a complete stop.

According to FMCSA, trucks are often 20 to 30 times heavier than passenger vehicles. The average weight of a car is about 2 tons (4,000 pounds), but the average weight of a semi-truck is around 40 tons (80,000 pounds).


It makes sense: The faster a vehicle is traveling, the longer it will take to stop. This reasoning applies to both passenger vehicles and semi-trucks.

Road Conditions

Snow, ice, or rain can significantly increase braking distance. Any adverse road conditions can have this effect.

Brake Systems

While most passenger vehicles have hydraulic brakes, which are liquid and shorten stop time, semi-trucks often have air brakes, which take more time to work.

When a truck driver first applies the brakes, air builds up across the length and breadth of the truck. After the buildup of air is complete, the brakes can begin to slow the vehicle. This process takes time, which adds to the stopping distance.

In other words, semi-trucks may have larger brakes than passenger vehicles, but those brakes have a lot more work to do.

How to Avoid a Truck Accident

Truck accidents are one of the most deadly types of roadway accidents in the United States. An accident with a semi-truck, whether caused by the truck or another vehicle, has a 98% chance of resulting in a fatality.

Keep stopping distance in mind, and follow these tips to avoid a truck accident:

  • Use caution when driving near tractor-trailers.
  • Stay out of blind spots. If you can’t see the driver in the side mirror, the driver cannot see you.
  • Keep a safe following distance between you and the truck in front of you.
  • Watch out for truck drivers making unexpected lane changes or exits.
  • Avoid cutting in front of a tractor-trailer or semi-truck.
  • Always leave an escape option when driving near a truck.
  • Give semi-trucks extra space for stopping whenever possible.

Nevertheless, accidents happen. Call an experienced lawyer if you are involved in a truck accident.

Contact a Truck Accident Attorney Today

If you or a loved one have been injured as a result of a truck accident, contact the Indianapolis Truck Accident Attorneys of Wilson Kehoe Winingham. The lawyers at WKW can help you get the compensation you deserve. Call 317.689.0654 or fill out an online contact form for a free, no-obligation case evaluation.

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