Big truck accidents are the deadliest type of collision on U.S. highways. Five plus tons of steel colliding with you at any speed will leave your car and those inside, at the very least, seriously damaged. Over the past decade, the number of big truck and 18-wheeler accidents have steadily climbed with 2017 culminating in 5,000 deaths, alone, and a great factor more injured.

But what is considered a “big truck?” The National Highway Traffic Safety Administration (NHTSA) defines a big truck as, “Any truck with a gross vehicle weight rating (GVWR) greater than 10,000 pounds.”

It is important to note, that the body composition and vehicle makeup do not designate a truck as a “big truck.” Just because it might not look like your typical 18-wheeler or construction vehicle, does not mean it is not classified as a big truck. This distinction could entitle you to much more compensation for injury and damage as trucking laws are much more strenuous than everyday civilian driving regulations.

With so much weight, it is easy to see how even the smallest detail going wrong at moderate speeds could lead to disaster for those traveling around the truck. Fortunately, truck behavior is fairly predictable if you know what to look for. If you are observant of the conditions, drivers around you, and the weather, you can make safe predictions of what might occur if disaster strikes.

Here are the most common types of big truck accidents, how they occur, and what you need to know.

Jackknife Accidents

A big truck jackknifed on the side of the road

Designated “the jackknife” because of its telltale shape, the jackknife is one of the most common big truck accidents you will see.

The Jackknife occurs when a truck tries to make a sudden and violent stop. The skidding halt causes the hitched trailers inertia to push forward on the cab and begin to swing back and forth wildly until momentum takes control and creates a 90-degree angle between the cab and the trailer.

With any sort of speed, the vehicle is likely to roll over and spill whatever it is carrying across the highway and into adjacent foliage. Cool if it is carrying a lifetime supply of Swedish fish, not so cool if it is carrying jet fuel or hazardous chemicals.

Ignoring the cargo for a moment, the biggest threat in a jackknife truck accident is the swinging trailer. When the truck driver loses control of the momentum, that trailer will be veering from lane to lane until, finally, momentum carries it fully to one side. The trailer could potentially swing out and hit other vehicles or span across several lanes forcing drivers to make sudden and immediate stops which could also cause a wreck.

So, we know the look of a jackknife and the potential dangers of a jackknife but why does it occur? There are several factors that can increase the chances of a big truck jackknifing:

First, excessive speeds. It takes a great deal of force to stop a truck; the higher the speed the more force required. When a driver needs to make a quick stop at high speeds, there is a greater chance they lose control.

Second, road conditions. Anything that makes the wheels on a truck lose traction puts the driver in great danger of losing control. Inclement weather where roads are slippery, excessively dry, or sleet see a three times increase in jackknife accidents.

 Third, is a light load. Contrary to what you might think, having more weight in the trailer is safer in regard to a jackknife. The added weight prevents the trailer from swerving back and forth. 


A large oil truck that rolled over in the street causing an accident with 2 other cars

A rollover is just as the name implies, a truck toppling over under the duress of its weight in an abrupt stop. Rollovers frequently happen when a driver tries to overcorrect – whether making an immediate stop or attempting to recover after a tire falls off the lip of the pavement. When the tire spills off the lip of the pavement, the separation between the pavement and the soft ground causes a rut and leaves the tire gripping at air. When a driver tries to overcorrect too fast and jerks the wheel back on the road, the sudden grip in traction causes the big truck to change direction quicker and topple over.

Rollover crashes are also incredibly speed dependent – much more so than non-rollover crashes – and even a marginal increase in speed can be the difference between a mere skid and a fatal crash. 40% of fatal rollover crashes involve excessive speeding and nearly 75% of fatal crashes took place where the speed limit was posted at 55mph or higher.

What makes a rollover so frightening is that once it begins to tip there is absolutely no way to regain control.  As mentioned in the previous section, the heavier the load, the less likely it is to jackknife but that added weight can make a rollover more likely. And once an 18-wheeler begins to roll, there is only one place for that cargo to go: out. Debris and cargo can be thrown wildly out onto the roads and damage cars, impair judgement, and pollute the surrounding environment.

The NHTSA reports that 35% of all traffic fatalities are due to rollovers. The most common causes of rollovers are: speeding, aggressive driving, and slippery roads.

Tire Blowouts

a tire on a big rig truck that has blown out

Tire blowouts are the most preventable accident on this list and, unfortunately, it 100% comes down to negligence by the driver and truck inspectors.

It is important to recognize that tire blowouts are not just flat tires; tire blowouts are the sudden and explosive rupturing of a tire wall from excessive heat and wear. The resulting explosion can leave the tire rubber in shreds and catapulting into nearby lanes. It can also get caught in the semi-trucks of other tires and cause the driver to overcorrect and lead to one of the two accidents already outlined above.

We have all been driving along the highway and seen the remains of such an occurrence. The long, torn strips of rubber that lay swaying in the breeze from speeding by cars. Curving, black husks that a truck will leave behind like a cicada leaves behind a shell on a hot summer day. They can be so small you don’t even register them, or they can be so large you are forced to change lanes.

Tire blowouts boil down to two main corroborating factors: Failing to inspect tires regularly and failing to replace tires when necessary. The Federal Motor Carrier Safety Administration (FMCSA) has a strenuous set of rules that truckers and trucking companies must adhere to in respect to tire care and inspection. It is an exhaustive list of rules but for the sake of brevity, I will sum it up here:

Truckers must systematically inspect their vehicle and tires after each successful trip. The truck must go through a pre-inspection and post -inspection. While on the road, truckers must inspect their tires at the end of each day. If any tire does not look fit to perform, the truck may not be driven until the tire is properly replaced.

Underride and Override Accidents

A car that has run into the side of the trailer of a big rig truck

Underride and override accidents are incredibly scary accidents that can leave the top of your car completely scissored off if severe enough.

First, the difference: Override accidents are when a big truck fails to stop in time and rides up onto a car in front of it. An underride accident is when a passenger vehicle collides with the trailer of a big truck and slides itself under the trailer.

Generally speaking, override accidents are the fault of the truck driver and underride are the fault of the passenger vehicle, but, as we know, not everything is so black and white. Here are some of the most common events that lead to override and underride accidents.

Override accidents can occur if a trucker is following too closely to another vehicle that has to make a sudden stop, there is low visibility from rain or fog, the truck driver failing to yield a right of way, a driver negligently changing lanes without checking his surroundings, brake failure, or a ire blowout.

Underride accidents most typically occur due to a motorist following too closely to a big truck or poor visibility, but here are some examples of how a big truck can be at fault for the accident.

The truck does not have properly functioning brake lights or tail lights, the mandated reflective tape on the trailer is dirty or not visible, the underride guards are missing, the driver does not signal changing lanes, or the driver parks on the shoulder without proper lighting.

All of these can lead to override and underride accidents and does not mean the truck driver is always liable. The trucking company can be held liable if the error was on part of the big truck driver or there was a mechanical problem with the vehicle. The passenger vehicle can be held liable or partly liable if it is found they were riding too closely or stopped too suddenly.


The front of a big rig truck with other trucks lined up behind it

The common theme you will see running through all these accidents is the #1 cause in all truck accidents: Human error. Each accident may have a different designation or name but the unchanging variable in every accident is the person behind the wheel. Negligence to follow laws, negligence to inspect vehicles, and negligence to listen to their own body.

Fatigue is the most common cause of driver error; about 40% of all truck accidents are attributed to fatigue.

This one, you would think, would be the easiest to avoid. Who would willingly give up sleep in favor of driving a truck? The answer seems to be the trucking companies. Trucking companies incentivize their drivers to forgo safety regulations and sleep in order to complete deliveries faster.

The most neglected safety regulation for big truck drivers is the hours of service regulation. It states that a driver may only spend 10 consecutive hours driving and 11 total hours on the road per day, with a minimum of 10 hours off between shifts. Drivers cannot exceed 60 hours on the road in one week and are required to take 34 consecutive hours off each week.

This break allows the drivers to sleep, collect themselves, and make the necessary inspections before heading back on the road.

The pressure to hit deadlines set by the trucking companies forces these drivers to ignore many of the laws in order to meet their internal pressures. Many driving pay incentives are dictated by how many jobs you complete and how quickly you complete them. This increased expectation also plays a big part in the opiate and prescription medication abuse we see in the truck driving community.

If you are in a truck accident and fatigue or hours of service regulation breach are deemed to be at fault you can go after the trucking company as well.


There are many different types of truck accidents. Knowing the signs can be the difference between life and death in many cases. Observe your surroundings - pay attention to the road conditions, weather, and your fellow drivers. Always drive cautiously around a big truck and do your best to stay well above or behind the truck.

If conditions are wet or visibility low, keep in mind jackknife and rollover accidents and stay well ahead or behind a truck with at least one lane of separation. If you are side by side with a truck do your best to quickly and safely pass the vehicle and remember tire blowouts. If you see a big truck swerving between lanes or veering off onto the lip of the road, quickly call the authorities; they will identify the truck and safely escort it off the road.

No one drives with the intent of getting in an accident and the same is true for truck drivers. Mistakes happen and as long as you are vigilant and mindful of your surroundings, you can drastically cut your odds of finding yourself in a collision with a big truck.