How Long Does a Semi-Truck Take To Come To a Full Stop?

How many times have you been riding down the interstate and had a fellow driver cut in tight on you? Most of us have had this happen. These errant drivers count on us to be able to quickly apply our brakes to avoid striking them.  Fortunately, when some drivers choose cut in front of others, most passenger cars operators are able to avoid a collision when this happens.

For commercial truck drivers, however, it’s a much different story. Semi-trucks simply can’t come to a full stop as quickly as passenger cars. Let’s look at the details as to why this is true:

Braking Is a Multi-Part Process

Many individuals tend to think of the braking process as a singular action.  Unfortunately, it is not.  It is a  3-part process that includes:

• Distance perception: This refers to how long a motorist travels as they try to determine if they are coming upon a hazard, watching to see what they do, and deciding how to best address the situation.
• Reaction time: Motorists must decide what type of evasive action they will take when they realize that impending danger lies ahead. The distance a vehicle travels as its operator takes decisive action when confronted with a hazard is the reaction time.
• Braking distance: A vehicle doesn’t come to an immediate stop once a motorist applies the brake. It takes time for the automobile to decelerate once the brakes are applied. The braking distance refers to the length a vehicle travels after its operator engages the brake pedal.

According to the 3-second rule of driving, it takes our brains a certain amount of time to register and react to hazards to avoid becoming involved in a crash.

How Long It Takes Motorists To Recognize Impending Hazards

The amount of time it takes motorists, including truckers, to react to stimuli, whether it’s a road construction zone, disabled vehicle, wildlife, stopped traffic, or something else, is something that researchers have long attempted to understand. They’ve studied it, intending to expand their knowledge about braking distance with the goal of making our roadways safer.

Researchers have concluded that three seconds is the bare minimum amount of time it takes passenger car operators to brake to avoid striking a car in front of them. They recommend five to six seconds to be safe, especially when motorists are traveling in less-than-optimal road conditions. 4.5 to 5.5 seconds falls within that range, especially considering not all vehicles have similarly functioning braking systems.

The average car is 12 to 18 feet in length and weighs 3,000-4,000 pounds compared to a truck that is between 45 and 65 feet and weighs 80,000 pounds. As you might imagine, a tractor-trailer that is 2.5 to 3.5 times the length and 20-30 times the weight of a passenger car will likely need significantly more time to stop than the 3-second rule calls for to ensure they don’t become involved in a truck accident.

How Long Does It Take a Semi-Truck To Stop?

There’s not a straightforward answer to this question as various factors dictate the distance with which a trucker can bring their 18-wheeler to a halt. However, researchers have made an effort to come up with some generalities.

One study published by the Utah Department of Transportation (UDOT) compared stopping distances between passenger cars and semi-trucks. UDOT officials determined that if both types of automobiles were traveling at the same rate of speed, then it would take the following amount of time to reach a complete stop:

• Passenger cars: 124 feet at 40 mph, 225 feet at 55 mph, and 316 feet at 65 mph
• Semi-trucks: 169 feet at 40 mph, 335 feet at 55 mph, 525 feet at 65 mph

While the stopping distances above are generally how long it takes passenger cars and tractor-trailers to come to a complete stop, that’s under ideal conditions. Some factors such as vehicle weight, truck and brake condition/maintenance/systems , weather conditions and road conditions may make typical stopping distances longer.

What Factors Impact Truck Stopping Distances?

Some situations that may create longer stopping distances of a truck than described above include the following:

• Vehicle weight: As referenced above, semi-trucks weigh a lot. Their weight can be as much as 80,000 pounds when loaded, which equates to 20 to 30 times the weight of passenger cars. The heavier an 18-wheeler or other type of truck is, the more distance it will need to reach a full stop.
• Weather conditions: Rain, snow, and ice are just some of many weather phenomena that can make braking take longer than most motorists (truckers included) might expect. One study by the American Safety Council detailed how roads are particularly dangerous during the first ten minutes after rain begins falling.
• Road conditions: The integrity of the roadway can also impact braking distance. It takes vehicles, trucks included, longer to stop on gravel surfaces or milled ones they may encounter in road construction areas where repaving may be underway. Oil slicks and the tar-based asphalt crack filler that exist on roadways can add to braking distances for truckers.
• Braking systems: Anti-lock brake systems (ABS) may generally have a capacity to stop quicker when engaged than conventional systems can. However, the opposite occurs (ABS have an increased stopping distance) on gravely and snowy road surfaces. Also, disc/disc brake systems may have an enhanced stopping power compared to disc/drum systems.

Another factor that may affect truckers’ braking distances is load shifts. Truckers with unsecured loads may experience a situation where their load is forced forward when they apply their brakes, causing their tractor-trailer to be propelled forward, which alters stopping distance.

Trucks’ braking systems also often fail when subjected to repeated force or friction, which can cause catastrophic brake failure, leading to a truck crash.

How Does a Lawyer Help After a Brake-Related Crash?

Trucking accidents tend to be more catastrophic than other types of crashes.  This is because many of the collisions they are involved in often involve much smaller passenger cars.

Motorists who are driving sedans that are struck by large trucks don’t make for a good match for one another in a crash. Motorists are often lucky if they walk away with recoverable injuries from such collisions.

Many drivers end up with life-changing, permanent injuries from truck accidents. These injuries carry a lifetime of pain and suffering, surgeries, physical therapy, or more dedicated (around-the-clock) care.

Our attorneys understand the hardships you might be going through if you or your family has been affected by a tuck accident injury. Contact us to schedule an initial no-cost consultation to learn more about how we can best help you and if you may be able to take legal action.