In an underride crash, a passenger vehicle slides underneath the truck, allowing the truck or trailer to strike the vehicle at windshield, window, or roof level rather than bumper-to-bumper.
There are three basic types of underride and override crashes:
A rear underride crash happens when a passenger vehicle strikes the back of a tractor-trailer or other large truck and slides underneath it.
A side underride crash occurs when a passenger vehicle strikes the side of a trailer and slides underneath it. Because trailers have long, relatively open sides, a side underride crash can allow the trailer to intrude deeply into the passenger compartment.
A front override occurs when a larger truck rides over or into a passenger vehicle from the front. The dynamics differ from a rear or side underride crash, but the result can similarly involve severe intrusion into the smaller vehicle’s passenger compartment.
Underride accidents can be especially dangerous because they can bypass the passenger vehicle’s protective structure. In an IIHS study of 115 crashes involving passenger vehicles striking the backs of heavy trucks or semitrailers, nearly half of the vehicles sustained severe underride damage; those vehicles accounted for 23 of the 28 fatal crashes studied.
The resulting harm can include:
Federal safety standards address some types of underride protection, but not all. Rear underride guards are required on most qualifying trailers and semitrailers, while side and front underride protection are not currently subject to comparable federal requirements. Understanding what the law requires—and what it doesn’t—can be important when investigating how an underride crash happened.
An underride guard is a strong metal structure attached to the back of a truck or trailer. It is designed to stop a passenger vehicle from sliding underneath the trailer in a rear-end crash.
Federal safety standards require qualifying trailers and semitrailers to have rear underride protection. FMVSS 223 sets performance requirements for the guard itself, while FMVSS 224 establishes requirements for rear impact protection.
You may also hear a rear underride guard called a Mansfield bar. “Mansfield bar” is simply a common name for a rear underride guard, not a separate federal safety standard. The nickname dates to actress Jayne Mansfield’s death in a 1967 crash involving a tractor-trailer, which helped draw attention to the dangers of vehicles sliding underneath trucks.
No. Federal requirements establish minimum performance standards, but they do not guarantee that a guard will prevent underride in every possible collision.
Speed, impact angle, the amount of overlap between the vehicles, vehicle height, guard design, and the forces involved can all affect whether an underride guard performs as intended.
The condition of the equipment matters, too. A guard that is missing, damaged, improperly attached, or inadequately maintained can raise different questions from one that was properly installed and maintained.
Unlike rear underride guards, side underride guards are not currently required by federal law on most commercial trailers. NHTSA has studied whether they should be required and is considering possible regulatory action.
The Stop Underrides Act 2.0, introduced in 2026, proposes federal performance standards for side, rear, and front underride protection. The bill has been introduced but is not currently law.
The absence of a side guard does not automatically mean someone was negligent. Liability depends on the facts of the crash, the applicable law, and evidence showing what caused the collision and resulting harm.
Investigating an underride crash may require more than looking at a photograph and asking whether a bar was present. Investigators may need to determine:
Those details can become important evidence in determining whether someone else’s negligence contributed to the crash.
Federal regulations establish important safety requirements for commercial trucks nationwide. But the laws governing an underride crash claim can vary depending on where the truck wreck occurred.
In Kansas and Missouri, differences in statutes of limitations, comparative fault, damage caps, wrongful-death rules, and other state laws can affect both the value of a claim and how it must be pursued.
The truck driver or carrier may be liable when negligent driving, following too closely, unsafe operation, or another violation contributes to the collision.
Truck cases can involve multiple responsible parties and a federal regulatory overlay that does not exist in an ordinary passenger-vehicle crash.
For example:
A thorough investigation may need to examine the driver, carrier, trailer owner, manufacturer, maintenance providers, insurers, and other entities connected to the truck’s operation.
Truck accident cases can involve evidence that disappears or becomes harder to obtain with time. Commercial trucks may generate electronic data concerning speed, braking, routes, and driver activity, while trucking companies maintain inspection, maintenance, driver, and vehicle records.
In an underride case, additional evidence may include:
A serious truck accident investigation is different from an ordinary car accident investigation. Evidence often extends well beyond the initial police report.
Your injury changed your life. The result of your case should help you reclaim it. We pursue every avenue available to secure meaningful compensation and a path forward.
Lawyers do more than meet deadlines and file paperwork. They also:
A lawyer can investigate how the crash occurred, identify potentially responsible parties, preserve evidence, obtain records, work with accident reconstruction and other experts when appropriate, and evaluate how the evidence fits together. An attorney can also handle communications and negotiations with insurance companies while you focus on recovering from your injuries.
A civil lawsuit does not necessarily end with a jury award, either. Many personal injury cases resolve through settlement before trial. A lawyer’s role is to build the case thoroughly enough to negotiate from a position of knowledge and leverage and to be prepared to take the case to trial if a fair settlement cannot be reached.
The value of an underride claim can also depend on much more than the severity of the vehicle damage. Injuries, medical expenses, lost income, future care needs, permanent impairment, evidence of liability, comparative fault, available insurance coverage, and whether the crash resulted in a death can all affect the damages available under applicable law.
After a serious underride crash, you shouldn’t have to figure out the legal and insurance issues alone. Contact DeVaughn James Injury Lawyers for a free case review to discuss what happened and what legal compensation you’re entitled to pursue.
To recover your monetary losses and demand justice to any wrong you have been subjected to, you must consult with a qualified truck accident attorney as soon as possible. Remember, the clock is ticking on your big truck wreck case.
With their profound knowledge and eye for detail, our truck accident lawyers can help you gather critical evidence in due time. We will get started on your case without delay in order to guard your interests and protect your claim from all opposing parties involved (trucking company, their insurance provider, and so on).
