In an underride crash, a passenger vehicle goes partly or fully under a trailer. A trailer's floor sits far above a car's bumper and hood, near windshield height. The car's crumple zones and airbags may never engage as designed, and the trailer itself can enter the passenger compartment. That is why underride crashes so often cause catastrophic head and neck injuries and deaths, even at moderate speeds.
There are two common patterns. In a rear underride, a car strikes the back of a trailer that is stopped, slowing, or parked on the shoulder, often at night or in rain. In a side underride, a tractor-trailer pulls across a road or makes a slow turn out of a driveway or truck stop, and a driver approaching in the dark does not see the long, unlit side of the trailer in time. On rural Florida highways such as US 27 and US 441, these crashes can happen at night near distribution centers and farm operations.
These cases usually turn on two issues: why the trailer was where it was and whether it was visible, and whether its rear guard, lighting, and reflective markings met federal rules and did their job.
1. Protect the vehicles before anything else
The trailer and the car are the central evidence. The rear guard's welds and bolts, any rust or prior damage, and how it bent or broke can show whether it was built and maintained to standard. Tow yards and insurers often dispose of wrecked cars within weeks, so we send written notice right away that neither vehicle be repaired, sold, salvaged, or crushed before inspection.
2. Send a preservation letter to the carrier and the trailer owner
The tractor and trailer are often owned by different companies. A preservation letter goes to each of them and asks them to save:
- The trailer, the rear impact guard, and any removed parts.
- Engine control module data, electronic logging device (ELD) records, and GPS or telematics data showing where the truck stopped and for how long.
- Camera footage from the truck, which many systems record over unless it is saved.
- Maintenance and inspection records for the trailer (49 CFR 396.3(b)-(c)), its most recent annual inspection report (49 CFR 396.21(b)(1)), and driver vehicle inspection reports (49 CFR 396.11).
- Dispatch messages, delivery appointments, and the driver's qualification file (49 CFR 391.51).
3. Check the rear impact guard rules
Federal rules require each trailer and semitrailer with a gross vehicle weight rating of 10,000 pounds or more "manufactured on or after January 26, 1998" to have a rear impact guard that meets the federal motor vehicle safety standard in effect when it was built, with listed exceptions such as pole trailers (49 CFR 393.86(a)(1)). The guard's bottom edge "shall not exceed 560 mm (22 inches)" above the ground at any point across its width (49 CFR 393.86(a)(3)), and its rear surface "must be within 305 mm (12 inches) of the rear extremity of the vehicle" (49 CFR 393.86(a)(4)). A guard that hangs too high, sits too far forward, or is bent or rusted from earlier damage may not stop a car from sliding under.
Federal maintenance rules state that "Parts and accessories shall be in safe and proper operating condition at all times" (49 CFR 396.3(a)(1)). A damaged guard that was never repaired is a maintenance failure.
“manufactured on or after January 26, 1998”
49 CFR 393.86(a)(1)
“Parts and accessories shall be in safe and proper operating condition at all times”
49 CFR 396.3(a)(1)
4. Look at lighting, reflective markings, and warning devices
Most trailers 80 inches wide or wider with a gross vehicle weight rating over 10,000 pounds, made on or after December 1, 1993, must carry a conspicuity system of retroreflective sheeting, reflex reflectors, or both (49 CFR 393.11(b)). That material makes a trailer visible in headlights at night. Dirty, faded, or missing markings are evidence.
When a commercial vehicle is stopped on the traveled road or the shoulder, the driver must turn on the hazard flashers immediately and, "as soon as possible, but in any event within 10 minutes," place warning devices behind the truck, including one about 100 feet back (49 CFR 392.22). Camera footage, ELD data showing when the truck stopped, and witness accounts can show whether that happened.
“as soon as possible, but in any event within 10 minutes,”
49 CFR 392.22
5. Reconstruct the driver's decision
In a side underride, the key issue is often why the driver pulled across traffic when an oncoming car could not see the trailer or stop in time. In a rear underride, it is often why the truck was stopped or crawling in a travel lane or on a dark shoulder. Engine data, GPS, and hours of service records help answer both. Federal rules bar a driver from operating while alertness is "so impaired, or so likely to become impaired" by fatigue or illness that it is unsafe (49 CFR 392.3).
“so impaired, or so likely to become impaired”
49 CFR 392.3
Florida rules that matter
Wrongful death. Underride crashes are often fatal. In Florida, a wrongful death action "shall be brought by the decedent's personal representative" on behalf of the survivors and the estate (§ 768.20, Fla. Stat.). Appointing one may require opening a probate estate, which takes time.
Deadlines. A wrongful death action must generally be filed within two years (§ 95.11(5)(e), Fla. Stat.). For injury claims arising after March 24, 2023, the general negligence deadline is also two years (§ 95.11(5)(a)).
Fault. Expect the trucking company to argue that the car's driver should have seen the trailer. Florida reduces damages by a claimant's share of fault and bars recovery for a person found more than 50 percent at fault for his or her own harm (§ 768.81(2), (6), Fla. Stat.). Lighting and reflective-marking evidence often answers that argument.
Insurance. Interstate for-hire carriers of nonhazardous property in vehicles of 10,001 pounds or more must carry at least $750,000 in public liability coverage (49 CFR 387.9). Trucks operating only within Florida must carry $50,000 to $300,000 per occurrence depending on weight (§ 627.7415, Fla. Stat.). The trailer owner may have separate coverage.
“shall be brought by the decedent's personal representative”
§ 768.20
Your checklist
- Ask in writing that the car and the trailer be held, not repaired or crushed.
- Get the crash report number, the carrier's name, and its USDOT number.
- Photograph the rear guard, the reflective markings, and the trailer's lights.
- Have a preservation letter sent to the carrier and the trailer owner.
- If a loved one died, speak with a lawyer about appointing a personal representative.
- Do not give a recorded statement to any trucking insurer.
- Act well before the two-year deadline.
How we handle these cases
Underride cases require fast work on the physical evidence. We secure the trailer and the car, bring in engineers and reconstruction professionals to measure the guard and evaluate the markings, and trace the trailer's ownership and maintenance. We represent injured people and families throughout Florida, including Miami-Dade, Broward, Palm Beach, Tampa, Orlando, and Jacksonville. Meetings are by appointment only. Call 305-748-3789 to talk with us.
This article is general information, not legal advice for your situation. Reading it does not create an attorney-client relationship. Past results do not guarantee a similar outcome.