The Terrible Cost of Truck Underride Accidents

Any collision between a passenger vehicle and a large truck or tractor-trailer is always going to be extremely dangerous, as the truck has the advantage of both size and weight over a car.  In accidents between passenger cars and large trucks, the vast majority of resulting serious injuries and deaths are to the occupants of the passenger vehicles.  Large truck accidents claimed the lives of 4,119 people in the U.S. in 2019 alone.  Perhaps the deadliest yet most preventable type of collision with a large truck is known as a truck underride crash.

What is an Underride Crash?

truck underride accident

Large trucks and tractor-trailers sit much higher off the road than the average passenger vehicle, such that their rear bumpers and side frames do not come close to matching up in a collision. In an underride accident, a car slides partially or completely under the truck or trailer, usually resulting in catastrophic injury or death to the occupants.

In an underride accident, the first point of contact with the side or rear of the truck is usually the car’s windshield. This means that most car safety features, especially the car’s front and rear crumple zones, don’t even come into play in an underride crash. Because of this, even low-speed underride crashes can be deadly to a vehicle’s occupants.

According to the Insurance Institute for Highway Safety, (IIHS), a non-governmental source of crash and safety data, there were 500 to 600 deaths per year [1] in the United States resulting from an underride collision where a passenger car struck a tractor-trailer from the rear or the side. To put it into perspective, that’s 50 people per month, or two deaths every day, from underride accidents.

It isn’t just passenger cars that are involved in underride crashes. Underride crashes can result and have resulted in the injury or death of motorcyclists, bicyclists, and pedestrians.

A senior research fellow at the IIHS stated that the IIHS estimates that underride occurs in 80-90% of tractor-trailer rear and side crashes where there are serious or fatal injuries. These are only estimates, as there is no standard way for police to report underride crashes, as discussed below.

Types of Underride Accidents

  • Rear underride crashes happen when a passenger vehicle hits and slides under the rear of a large truck or tractor-trailer. In some cases, the driver of the passenger vehicle is following too closely, and/or the truck ahead of them slows down or stops abruptly.  In other cases, a passenger car will rear-end a truck that has parked on the side of the roadway, especially if the truck is not displaying adequate hazard/warning lights or other markers, or under poor lighting conditions.  Rear underrides can also occur in poor weather conditions, such as when a car slides on wet or icy roads under the rear of the trailer.
  • Side underride accidents happen when a car crashes into the side of a truck or trailer and slides underneath, either partially or completely.  These accidents can easily occur at night when a truck is making a U-turn and the other vehicle’s driver cannot see the truck because of reduced visibility. Another common side underride scenario is when the truck is crossing or turning in front of a passenger car, believing other drivers can see them.  Side underride crashes can also result from a large truck merging into a highway lane where a smaller vehicle is present but not perceived by the truck’s driver.
  • truck accident front underrideFront underride collisions occur when a truck drives over a smaller vehicle, causing it to lodge under the front of the truck. In a study of underride accidents in 1997, the IIHS found that 57 percent of these crashes involved the front of the truck.  A common cause of these crashes involves poor truck maintenance, specifically of the brake system.  A partial or complete brake failure could easily lead to a front underride crash.  Other causes can be inattention or distraction on the part of the truck driver and following too closely.

Rear Guards, Side Guards, and Front Guards

Rear guards have been required on large trucks and tractor-trailers since 1998.  However, several types of trucks are exempt from the rule, including so-called “single-unit trucks.”  Single-unit trucks are the type where the cab and cargo area are mounted on a single chassis and include home heating oil delivery trucks, dump trucks, garbage trucks, and box trucks.  Also exempt are trucks with rear wheels set very close to the back of the trailer, and various types of special-purpose trucks.  Single-unit trucks, therefore, offer no underride protections for passenger vehicles.

For trucks that are required to have rear guards, the IIHS found in a series of crash studies in 2010 that many of these guards fail to stop catastrophic underride crashes.[2]  Both the IIHS and the National Highways Traffic Safety Administration, (NHTSA), among many other groups, have been pressing the federal government to upgrade the standards for rear guards.  Canada has required upgraded rear guards since 2007.  The good news is that many trailer manufacturers are already building their new models to these higher standards, but many older trailers are still in active service on American roadways.

Unfortunately, there are currently no regulations that require large trucks and tractor-trailers in the U.S. to have either front or side guards, even though there is proof these could save many lives and lessen the occurrence of serious injuries.  Many European nations already require front guards on their large trucks for this same reason.  In the U.S., there are efforts underway to require side guards, but they have yet to become law.  The National Traffic Safety Board, (NTSB) has recommended side guards for all large trucks, but industry stakeholders have been pushing back.

Preventing Underride Accidents

In addition to requiring better rear guards, as well as front and side guards on all large trucks and tractor-trailers, other measures could be taken to reduce the number of underride accidents on our roadways.

  • truck accidentsBetter inspections. Just because a truck is equipped with a rear guard does not mean it will prevent an underride crash.  Many guards have rusted or otherwise fallen into disrepair, making them less effective in a crash.  Improved inspection standards by state authorities to specifically require a yearly evaluation of the rear guard could reduce the number of injuries and fatalities from underride.
  • Better reporting. One of the difficulties in convincing lawmakers to improve the safety of large trucks and tractor-trailers is the lack of accurate statistics on underride crashes.  There is currently no uniform, national standard for reporting an underride crash on a crash report filled out by police.  Also, many police officers have not been trained to correctly recognize underride crashes. Because of this, underride accidents are almost certainly underreported.  A nationwide standard for the reporting of underride accidents would yield data that would allow legislators and regulatory bodies to craft better standards.


Hundreds of people are seriously injured or killed due to underride accidents each year.  Better safety technology already exists to prevent most of these unnecessary tragedies.  An improved state-by-state reporting system for traffic accidents that takes into account underride crashes is needed, as well as better training for traffic officers.  Finally, lawmakers and regulators at the federal level can work with the trucking and transport industries to implement better truck safety features.

Contact an Attorney

If you or anyone you know has been injured in an automobile accident of any kind, the attorneys at Martin, Harding & Mazzotti, LLP have a wealth of experience in dealing with insurance companies and in protecting your rights to receive the compensation you’re entitled to.  Our attorneys handle all types of motor vehicle accidents, including those involving automobiles, motorcycles, and all types of truck accidents, from eighteen-wheelers to delivery vans. Contact us today for a free case evaluation by calling 1-800-LAW-1010 (1-800-529-1010). We’re here 24 hours a day, 7 days a week to take your call, or use our convenient online contact form here.

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