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How Long Does It Take an 18-Wheeler Semi Truck To Stop

Did you know that there are around 8 million truck drivers employed in the U.S. right now? 

Semi truck drivers know that driving an 18-wheeler requires a great deal of caution. The majority of the country’s goods get transported by giants of the road known as semi-trucks.

Trucks are 26 times heavier than the typical on-road car, weighing up to 80,000 pounds. This makes learning how to stop a tractor-trailer a very vital ability that could save lives. Continue reading to learn how long it takes an 18-wheeler semi truck to stop.

NHTSA Stopping Requirements for Semi Trucks

The National Highway Traffic Safety Administration (NHTSA) is in charge of maintaining road safety. It’s crucial for drivers to know when and how to stop at a safe distance when operating semi-trucks.

Drivers don’t need to be experts in physics to comprehend braking regulations. In order to stop a semi-truck safely, the NHTSA published a distance chart that takes into account both the vehicle’s speed and braking system.

In order to stop a semi-truck safely, the NHTSA published a distance chart that takes into account both the vehicle’s speed and braking system.

Currently, trucks were tested under three separate scenarios. The stopping distance for each circumstance is described as follows:

  • Loaded: when stopping from 60 mph, single-unit trucks must do so within 310 feet, while air-braked truck tractors must do it within 355 feet.
  • Unloaded: single-unit trucks and truck tractors must come to a complete stop within 335 feet at a speed of 60 mph.
  • Emergency braking condition: single-unit trucks must stop at 613 feet and tractors at 720 feet at 60 mph under

Large vehicles must often have longer stopping distances since stopping a larger mass demands more space. This makes it clear that semi trucks take longer to stop than regular vehicles.

How Much Longer Does a Semi-Truck Take to Stop Compared to a Car?

When occupied, a passenger car weighs between 3,000 and 4,000 pounds. It would take 316 feet to stop a car that weighs 4,000 pounds and is moving at 65 miles per hour. An 80,000-pound 18-wheeler, on the other hand, would need 525 feet to stop in identical circumstances.

The examples described above are ideal situations, which is significant. It frequently takes more distance to stop a fully-loaded semi due to certain road conditions.

Factors That Affect the Stopping Distance of a Semi Truck

There are other aspects than a truck’s weight and brake quality that affect how quickly it can come to a halt. Listed below are three variables that affect the amount of time it takes to stop a truck:

  • perception distance
  • response time
  • braking distance

Perception distance is the distance a truck travels after a driver becomes aware of an incident. The duration of this stage can change depending on how aware a driver is, the state of the road, and any additional elements that may influence a driver’s reactions, such as the use of alcohol or drugs.

The amount of time it takes a driver to effectively respond to a situation is reaction time. Similar to perception distance, reaction time is also influenced by the person, their level of alertness, and outside variables like the effects of drugs.

The term “braking distance” refers to the time it takes for a truck to come to a complete stop once the driver applies the brakes.

The Effects of Speed on Stopping Distance

It’s critical to realize that speed does not affect a truck’s stopping distance proportionally while talking about the topic. A driver’s stopping distance does not double just because they double their speed.

Generally speaking, an increase in speed has a four times greater influence on stopping distance. So, if they increase their speed, stopping completely could take four times longer.

In addition, if they do crash, the truck will have four times the devastating power. Therefore, if drivers slow down a little on the road, they increase their chances of avoiding collisions and decrease the likelihood that fatalities will occur in the event of a collision.

Why Stopping Distance Factors Matter

All three stopping distance parameters must be taken into account since they have a big impact on how long it takes an 18-wheeler to stop.

While the aforementioned example claims that stopping a truck requires around 525 feet, this number only accounts for the truck’s braking distance given its weight and speed.

It may take hundreds of additional feet to stop a truck safely due to perception distance, reaction time, and other factors.

Air Brakes vs. Hydraulic Brakes

Although hydraulic brakes are typically used on smaller vehicles, air brakes are typically used on larger trucks. Even though it’s doubtful that anyone will ever drive a truck with hydraulic brakes, understanding the two variations can be helpful.

A liquid is used by a hydraulic brake to exert force on objects. Brake fluid is the liquid media employed in automobiles. From its reservoir, this fluid is sucked into the master cylinder. When the pedal is depressed, it is then forced outward against the brake lines.

Smaller vehicles frequently use hydraulic brakes for two reasons. First, because of the comparatively light design, the liquid has a strong stopping power for the wheels. Second, a hydraulic system requires far less space than an air one and may therefore easily fit into the frame of a smaller car.

Larger and heavier vehicles are the main uses for air braking systems. The system provides braking force for locomotives, big trucks, buses, and other large vehicles.

While an air brake and a hydraulic brake have similar mechanical designs, they differ in the amount of force required to stop the vehicle. To completely stop a heavy-duty vehicle, something far stronger than breaking fluid is required.

This brake system functions in the opposite manner to regular brakes to guarantee that a truck always has the stopping power it requires. To put it another way, the brake is constantly applied.

The mechanisms are pushed into position by strong springs and held there until adequate air pressure is present to disengage them. The vehicle can move because of the pressure keeping the mechanism away from the wheels.

So, when a driver applies the brakes, the system lets out the trapped air, and the spring forces the mechanism back into a stopping position. That pressure then starts to increase.

Semi Truck Brake Lag

Brake lag is a fourth element that may make it more difficult for semi-trucks to stop. While 18-wheelers often use air brakes, passenger vehicles typically have hydraulic braking systems.

Air brakes take some time to start working after being actuated, in contrast to hydraulic brakes, which start working immediately as the brake pedal is depressed.

Before the brakes engage when a truck driver presses the brakes, air must accumulate throughout the system. Even though it might only take a second, brake lag can have a big impact on how long it takes an 18-wheeler to stop and how severe an accident is.

Driving Safely Around Semi Trucks

You might be persuaded to avoid trucks on the highway due to the enormous trucks’ long stopping distance, the possibility of brake failure, and/or a trucker who is disoriented or exhausted and hesitant to apply the brakes.

However, because of their wide blind areas and restricted mobility, heavy trucks and buses pose a serious safety risk to drivers of smaller vehicles.

A commercial truck has enormous blind zones in the front, back, and on either side of the vehicle. Avoid parking too close to or behind a truck.

When driving next to a truck, the blind spot extends two lanes to the right and one complete lane to the driver’s left. Assume the truck driver can’t see you if you can’t see him or her in the side mirrors of your car.

Even if the truck driver sees you, the brake lag distance may prevent the trucker from slowing down in time to avoid colliding with you. When following a truck, keep a good distance behind it so you can be seen.

Stay back when you stop as well since a truck’s gears may not engage when it restarts, causing it to roll backward. Trucks require more space for turning, thus they might swing widely or begin a turn from the middle lane. Never try to pass a truck on a tight corner.

Have You Been In an Accident With a Semi Truck In Houston, Texas?

Trucks are more difficult to stop than other types of vehicles, however, it is the responsibility of the driver to operate within the vehicle’s safety limitations.

When a driver misses their stop and collides with another car, it’s frequently because they didn’t give themselves enough room to stop safely or were driving too fast for the road conditions.

Call O’Hara Law Firm right away if you’ve been in a truck accident that could have been avoided. On behalf of drivers, our truck accident attorneys have won countless settlements. After major accidents, we fight for the explanations people need and insist on the money they need to rebuild.