Underride Accident Lawyer in Louisville, Kentucky

There are two main types:

• Rear underride. A car hits the back of a trailer that is stopped, slowing or parked. This often happens at night, on a shoulder, in a work zone, or where traffic backs up on I-65, I-64 or I-71.
• Side underride. A car hits the side of a trailer that is turning, crossing a highway, or backing across the road into a driveway or loading dock, often in the dark.

Single-unit trucks, like dump trucks and box trucks, can cause underride crashes too when their beds sit high off the ground.

Federal rules require most large trailers to carry a rear impact guard, the steel bar across the back:

• Trailers built since January 26, 1998. Trailers and semitrailers with a gross vehicle weight rating of 10,000 pounds or more must have a rear impact guard meeting Federal Motor Vehicle Safety Standards 223 and 224 in effect when the trailer was built (49 CFR 393.86(a)).
• Height and width. The bottom of the guard can be no more than 22 inches off the ground, and it must reach within 4 inches of each side and sit within 12 inches of the back of the trailer.
• Older vehicles. Many older trucks and trailers that ride more than 30 inches high must have a guard no higher than 30 inches off the ground (49 CFR 393.86(b)). Truck tractors themselves are exempt.
• Exceptions. Pole trailers, pulpwood trailers, low-chassis vehicles, special-purpose vehicles, "wheels back" vehicles and certain road-construction trailers are exempt from the newer-trailer rule.

Stronger guards for newer trailers. In 2022, the National Highway Traffic Safety Administration upgraded the guard standards. Guards on newly built trailers must protect occupants of small cars in 35 mph crashes, both straight-on and when half the car overlaps the trailer. The compliance date was July 15, 2024 (87 FR 42339).

Guards must be inspected. Since 2021, rear impact guards have been on the list of items checked in each truck's required annual inspection (86 FR 62105; 49 CFR 396.17). A bent, rusted or missing guard is a maintenance failure.

Why guard condition matters so much. A guard only works if it holds. Corroded welds, missing bolts, a guard hanging lower on one side, or a horizontal bar that has been struck and bent can all let a car push through or slide under at speeds a sound guard would have stopped. Engineers compare the guard's condition and attachment to the standard that applied when the trailer was built, and to the damage on the car.

As of October 2026, no federal rule requires side underride guards on trailers. Congress directed the Department of Transportation to research them in the 2021 Infrastructure Investment and Jobs Act. NHTSA published an advance notice of proposed rulemaking in April 2023 (88 FR 24535) and formed an Advisory Committee on Underride Protection, but it hasn't proposed a requirement.

That doesn't end a side-underride case. The claim usually turns on how the truck was being operated: a driver pulling across a highway in the dark, backing into traffic, or blocking lanes without warning.

• The truck driver, for stopping on a shoulder without flashers and warning triangles (federal rules require triangles within 10 minutes; 49 CFR 392.22), for sudden lane blocking, or for unsafe turns and backing.
• The motor carrier, both for its driver and for its own failures: skipped inspections, damaged guards left in service, and missing or dirty reflective markings.
• The trailer owner or lessor, which may be a separate company from the carrier.
• Repair shops that welded or "fixed" a guard improperly.
• The guard or trailer manufacturer, when a guard fails because of its design or construction. Kentucky's product liability law (KRS 411.300–411.350) applies. Manufacturers often rely on the presumption that a product met industry standards when it was built, and on the presumption that it wasn't defective if the crash happened more than five years after the first sale or eight years after manufacture (KRS 411.310). Both presumptions can be rebutted with evidence. See product liability.

Insurers often argue that the driver of the car caused a rear underride crash by not stopping in time. Kentucky's pure comparative fault rule (KRS 411.182) compares everyone's share:

• The car driver's
• The truck driver's, for an unlit trailer, no triangles, or a stop in a travel lane
• The carrier's, for a guard that shouldn't have been on the road
• A manufacturer's, for a guard that failed

The question isn't only who hit whom. It's also why a crash that might have been survivable wasn't.

• The trailer itself. Photograph and measure the guard before the trailer is repaired, scrapped or sent back into service.
• The trailer's build date and specifications, from the VIN plate and manufacturer records, to find out which guard standard applies.
• Inspection, maintenance and repair records for the guard, lights and reflective tape.
• Truck data, including the ECM, ELD, GPS, and forward and rear cameras. See black box and ELD evidence.
• Scene evidence: lighting, warning devices, police photos and video from other drivers.

A preservation letter needs to go out right away. Trailers are often repaired and back on the road within days.

• Don't let the trailer leave without documentation. Ask the police which tow yard has it, and tell your lawyer immediately.
• Keep the car as well. Its damage shows how the guard performed.
• Write down the trucking company's name, DOT number and trailer number from the police report.
• Refer the trucking company's insurer to your lawyer.

Underride crashes cause traumatic brain injuries, spinal cord injuries and other catastrophic injuries, and they are often fatal. See our wrongful death page. Damages can include lifetime medical care, lost earning capacity, pain and suffering and, in cases of truly reckless conduct, punitive damages.

PIP from the car's own insurance usually pays first, up to $10,000 per person. See how Kentucky PIP works.

Claims against the truck driver and carrier generally must be filed within two years of the injury or the last PIP payment (KRS 304.39-230(6)). Claims against a manufacturer may face a different and shorter deadline, so plan around one year. See our statute of limitations guide.

• Send preservation demands for the trailer, guard and truck data
• Work with engineers and reconstructionists on guard performance
• Pull the carrier's inspection and maintenance history
• Identify every defendant: driver, carrier, trailer owner, repair shop and manufacturer
• Prepare for trial from day one. Larry Forman has tried 50+ jury trials and won 95% of them.

Learn more about Larry Forman, see our case results (past results don't guarantee a similar outcome), or return to our truck wreck and commercial vehicle crash pages.