Underride Truck Accidents in Illinois: A Deadly and Preventable Crash

**Underride accidents occur when cars slide under truck trailers, often causing fatal injuries.** Properly functioning underride guards are required by federal law and can prevent these catastrophic crashes. Failure to maintain safety equipment creates liability for the trucking company.

A sedan approaches a tractor-trailer that has slowed or stopped on the highway ahead. The car slides beneath the rear or side of the trailer, and the trailer’s edge strikes at windshield height, shearing off the roof of the passenger compartment. This is an underride crash, and it is among the most lethal types of collisions on American roads. Many of these deaths are preventable with equipment that has existed for decades.

How Underride Accidents Happen

Underride crashes occur when a smaller vehicle passes beneath the body of a large truck or trailer. There are two primary types. A rear underride happens when a vehicle strikes the back of a trailer, typically because the truck stopped or slowed suddenly, was poorly lit, or was parked without adequate warning. A side underride occurs when a vehicle collides with the side of a trailer during a turn or at an intersection, passing beneath the gap between the trailer floor and the road surface.

The physics are devastating. Standard passenger vehicle safety systems, including crumple zones, airbags, and seatbelts, are designed to absorb frontal or angular impacts. They are not designed for a scenario where the vehicle’s occupant compartment passes under a rigid steel structure. The result is often decapitation, catastrophic head trauma, or fatal crush injuries to the upper body.

Federal Rear Guard Requirements and Their Limits

Federal Motor Vehicle Safety Standard (FMVSS) 223 and 224 require trailers manufactured after 1998 to have rear impact guards, commonly called ICC bumpers or Mansfield bars, named after actress Jayne Mansfield, who died in a 1967 rear underride crash. These guards are designed to prevent passenger vehicles from sliding beneath the trailer at speeds up to 30 mph.

The problem is that many real-world crashes happen at speeds well above 30 mph, and the guards often fail. The Insurance Institute for Highway Safety (IIHS) has tested rear guards and found that many do not withstand moderate-speed offset impacts. Stronger guards, such as those meeting the IIHS TOUGHGUARD standard, perform far better but are not federally mandated. There is currently no federal requirement for side underride guards at all, despite years of advocacy and proposed legislation.

Liability in an Underride Crash

An underride case can involve several theories of liability. The truck driver may be negligent for stopping in a travel lane without activating hazard lights, for failing to use reflective triangles as required by FMCSR 392.22, or for making a turn without yielding the right of way. The motor carrier may be liable for failing to equip trailers with adequate guards, for using trailers with damaged or non-compliant guards, or for inadequate lighting and reflective markings.

In some cases, a product liability claim against the trailer manufacturer or guard manufacturer is appropriate, particularly if the rear guard failed at a speed within its design parameters. Illinois product liability law allows claims based on strict liability, negligence, or breach of warranty. As discussed in our overview of Peoria truck accident claims, building a strong case means identifying every party whose negligence contributed to the crash.

Damages in Underride Cases

Because underride crashes so often result in death or catastrophic injury, the damages tend to be substantial. In a wrongful death case, the representative of the estate can recover damages for the grief, sorrow, and mental suffering of the surviving spouse and next of kin under the Illinois Wrongful Death Act (740 ILCS 180). The Survival Act (755 ILCS 5/27-6) allows recovery for the decedent’s conscious pain and suffering between the time of injury and death. In cases involving survivors, damages may include lifelong medical care, permanent disability, traumatic brain injury treatment, and the profound loss of quality of life that follows a catastrophic head or spinal injury.

Investigating an Underride Crash

Evidence in these cases is highly technical. An accident reconstruction expert can analyze the point of impact, the speed of both vehicles, and the performance of the rear or side guard. The truck’s ECM data will show speed, braking, and whether the driver was decelerating before the collision. Photographs of the trailer guard, the vehicle’s roof line, and the overall crash scene are essential. Maintenance records should show whether the guard was properly attached and in compliance with federal standards. If the trailer had damaged or missing reflective tape or inoperative marker lights, those failures may have contributed to the crash by making the trailer invisible to approaching drivers.

Frequently Asked Questions

Are side underride guards required by law?

Not at the federal level. Several bills have been introduced in Congress to mandate side underride guards, but none have been enacted as of early 2026. Some carriers voluntarily install side guards, and several other countries require them. The absence of a legal mandate does not prevent you from arguing that a reasonable carrier should have installed them, particularly when the technology is proven and available.

Can I file a lawsuit if a family member died in an underride crash?

Yes. Under the Illinois Wrongful Death Act, a personal representative of the deceased person’s estate can file a lawsuit on behalf of the surviving spouse and next of kin. The claim may be brought against the truck driver, the motor carrier, and potentially the trailer or guard manufacturer. There is a two-year statute of limitations from the date of death.

What if the truck was parked on the side of the road?

FMCSR 392.22 requires drivers of disabled vehicles to place reflective warning devices within 10 minutes of stopping. If the driver failed to do so, or if the truck’s hazard lights and reflective markings were inadequate, the driver and carrier may be liable for the crash. Parking in a travel lane or on the shoulder without proper warning is a well-recognized basis for negligence claims.

If a trucking accident has left you or your family facing mounting medical bills, the Parker & Parker personal injury team can help.

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