Safety on the Road: Common Causes of Semi-Truck Accidents

If a semi-truck is involved in an accident, the results are usually catastrophic. Cargo dislodged from a semi-truck could cause serious harm to smaller vehicles in its vicinity—and lead to serious injuries and even death in many cases. According to the Federal Motor Carrier Safety Administration (FMCSA), large truck and bus accidents caused over 4,000 deaths in the US during 2017. Other people have suffered life-changing injuries from the more than 100,000 accidents involving large trucks in the same year. To practice better road safety, equip yourself with a deeper understanding of why accidents occur—including the causes of semi-truck accidents.

Safety on the Road Common Causes of Semi-Truck Accidents 1

Whether you`re a semi-truck driver or another kind of road user, such knowledge can help you avoid or deal with accidents if they occur.

In this article, you`ll learn about common causes of semi-truck accidents.

What Is A Semi-Truck?

A semi-trailer truck—usually referred to as a semi-truck, semi, or 18-wheeler—comprises a combination of one or more trailers for carrying freight, and a tractor unit which the trailers attach to. They have a forward engine, a steering axle, and drive axles. The truck can drive on its own without having a trailer attached to it.

Common causes of semi-truck accidents in the United States include the following:

  • Prescription drug use.
  • Traveling too fast.
  • Use of over-the-counter drugs.
  • Fatigue.
  • Alcohol.
  • Illegal drug use.

Below, we`ll discuss each of these causes in more detail. 

1. Prescription Drug Use

Any drug can impair a driver’s focus, including prescription drugs normally used for improving one`s chronic health conditions. In fact, prescription drugs are one of the most common causes of commercial truck accidents.

While these drugs are prescribed by licensed physicians, they could still impair a driver’s focus on the road. Prescription drugs can inhibit or stimulate certain hormones and neurotransmitters. This can negatively affect cognition, motor (movement) skills, hearing, vision, and other important senses. If your doctor prescribes medicine, ask them if and how it will affect your overall focus and driving skills.

The following drugs can affect a driver`s ability and focus on the road (this is not an exhaustive list):

  • Psychotropic drugs are used to treat signs and symptoms of psychological disorders, like depression.
  • Sleep aids can negatively affect a driver`s perception.
  • Pain relievers can make a driver drowsy while on the road, especially if the trip is long, and the driver has no company to ease their boredom.
  • Stimulants are meant to increase activity in a person`s central nervous system, but they can cause focus problems for certain drivers.

2. Traveling Too Fast

If a truck travels too fast, it has a higher chance of causing an accident because of the weight it carries. Based on an analysis of truck rollover crashes, a truck traveling along a curved path has a high centrifugal force, causing it to lean away from the curve’s direction.

If it goes too fast, the truck overturns, resulting in a `rollover.` A semi-trailer truck is highly vulnerable because its center of gravity is high, and its load is typically unstable.

3. Use Of Over-The-Counter Drugs

Over-the-counter (OTC) drugs can be bought at the pharmacy without presenting a doctor`s prescription. Semi-truck drivers may use over-the-counter drugs to treat minor conditions, such as colds or allergies, without being aware of the drugs` effects on their cognitive and motor abilities.

Some examples of OTC medications that can impair driving abilities include cough and cold medicines, cardiovascular medicines, antihistamines, and pain relievers. These medications can cause the following:

  • Impaired coordination.
  • Fatigue.
  • Balance problems.
  • Delayed reaction time.
  • Impaired spatial judgment.

4. Fatigue

A semi-truck driver spends many hours behind the wheel. Many truck drivers try to split hours by following the 14-hour drive rule. If a driver starts the day at 5:00 or 6:00 AM, they must stop no later than 7:00 or 8:00 PM. 

However, many semi-truck drivers feel pressured to drive, even if they are exhausted. Because of deadlines and counted paid and unpaid hours, they risk their own and other drivers` lives on the road. Most times, if a semi-truck driver is not driving, they`re not getting paid. Being paid by the mile makes them spend many more hours driving—pushing themselves to complete more miles—while they should be taking adequate breaks to rest.

Here are some tips to avoid fatigue while on the road:

  • Consume foods that produce less gas and cause bloating. Avoid beans and lentils, cabbage, cauliflower, mushrooms, peas, onions, and asparagus.
  • Exercise to reduce restlessness. Exercising also lets you move and stretch your other muscles aside from the ones you use when sitting and driving all day.
  • Use earplugs, eye masks, and white noise machines to block out any light, noise, or distractions when sleeping.
  • Slow down, park, and get some rest if your body signals that you need it.

5. Alcohol

While you may be confident that you’re a skillful truck driver, it’s not an excuse to drink alcohol while driving. You may not feel different after drinking and still get on the road with your truck. But it can cause dangerous situations such as hitting someone who is crossing the road or crashing into a smaller vehicle.

Never consider using alcohol when you’re driving. Even drinking a little can encourage you to consume more than what your body and mind can handle, because the effects of alcohol may not show immediately.

6. Illegal Drug Use 

Illegal drugs include cocaine, cannabis (in certain states), heroin, methamphetamine, etc. Semi-truck drivers may take illegal drugs to avoid feeling sleepy on the road and to increase their energy levels. However, these drugs can compromise road safety by severely impairing driving abilities.


Knowing the common causes of semi-truck accidents empowers you to avoid situations that can cause serious injury and even death. Avoid road accidents by educating yourself about how prescription drugs may affect your driving abilities, getting enough sleep in between driving sessions, and avoiding alcohol when driving.

Following the above tips will reduce your risk of getting in an accident on the road while driving a truck, a car, or any other vehicle.