Stopping Distances for Commercial Vehicles

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Due to the potential for serious damage, the trucking industry is highly regulated. Truck drivers must follow a complete set of rules regarding the amount of miles that they can drive in a day, the number of hours a day that the truck driver can travel and when they must take breaks. The large nature of commercial vehicles makes them a potentially dangerous object on the roadways. As such, truck drivers must take their stopping distances into consideration.

Scientific Data

A normal passenger vehicle such as a car or small pickup truck will normally take approximately 316 feet to come to a complete stop after recognizing the need to stop. In comparison, a semi truck takes about 525 feet before it comes to a complete stop after recognizing the need to stop. This is an important aspect of a truck accident case as the stopping distance is often a question answered through accident reconstruction. To accurately calculate the stopping distance of the vehicle, different factors are taken into consideration.

Reaction Distance

One such factor is the perception of an impending danger. The driver of a passenger vehicle usually takes 1.5 seconds to perceive a dangerous situation and apply the brakes. This time is about the same for the average truck driver.


Another factor that impacts the time it takes for the vehicle to stop is the weight of the vehicle. Even though semi trucks have larger brakes than other vehicles, it usually takes the semi truck much longer to stop because of the much larger weight of the semi truck. Cars have an average weight of 5,000 pounds while a semi truck can weigh up to 80,000 pounds.

Therefore, a car takes about 124 feet to come to a stop when traveling at 40 miles per hour from the time that the driver perceives the danger. In comparison, a truck driver takes approximately 169 feet from the danger perception time when traveling at the same speed.


A critical component of calculating stop times is to know the speed that the vehicle was traveling right before the accident. The faster the vehicle is traveling, the longer it will take to come to a complete stop. In comparison to the figures noted above, a passenger vehicle will take about 316 feet from the awareness point when traveling 65 miles per hour. The semi truck takes about 525 feet before coming to a complete stop.

Height and Perception

Another factor that may come into play in a truck accident is the height of the vehicle. Truck drivers may be able to see potential dangers sooner due to their ability to see further distances at their elevated position. When the truck driver perceives the potential danger sooner, he or she can take steps to avoid or minimize the danger. When commercial trucks or passenger vehicles are close to other vehicles because they are traveling too closely, they cannot perceive potential dangers in front of them and will have less time to react.

Other Variables

There are a variety of other variables that can impact the stopping distance of semi trucks. For example, weather can play a major part. When there is rain, snow or ice on the roadway, braking distance is increased significantly. Road conditions can also be an important variable in determining the anticipated stopping distance of a semi truck. Additionally, the tire treads and the manner in which the brakes are applied can affect the stopping distance of semi trucks. Factors that affect the driverís ability to recognize a danger can also impact the calculation.

Onboard Computers

Most contemporary commercial vehicles have an onboard computer that stores important data about the commercial vehicle. This data may include the speed that the vehicle was traveling before the accident and the time when the brakes were applied. This data can be analyzed after an accident to help piece together the moments right before an accident, information that is often critical to the case. The type of data that is available depends on the onboard computer and the manufacturer.

Legal Assistance

Individuals who are involved in a truck accident case may wish to consult a personal injury lawyer. A party to a truck accident case can discuss the availability of onboard computer data and different ways to determine the braking distance of the commercial vehicle that is at the heart of the case. He or she may discuss the factors that may have played a part in impacting the braking distance.


Disclaimer: While every effort has been made to ensure the accuracy of this publication, it is not intended to provide legal advice as individual situations will differ and should be discussed with an expert and/or lawyer. For specific technical or legal advice on the information provided and related topics, please contact the author.

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