Who Is Liable When a Car Slides Under a Truck? New Guide Explains

The León Law Firm has published a guide to underride truck accidents in Texas, covering liability, evidence, and damages, as NHTSA continues reviewing whether to mandate side underride guards that aren't currently federally required.

Sugar Land, United States, September 18, 2026 /NewsNetwork/ -- SUGAR LAND, Texas — The León Law Firm, P.C. has published a guide on underride truck accidents, crashes where a passenger vehicle slides underneath a tractor-trailer, explaining who can be held liable when one happens and why the answer is rarely just the driver. The guide arrives as federal regulators keep reviewing whether to require side-mounted guards that could help prevent these crashes.

Rear impact guards, the steel bars hanging beneath the back of most trailers, have been federally required for years under 49 CFR Section 393.86. No equivalent rule covers the sides of a trailer. A car that crosses into the open gap along a trailer's side can slide underneath it as easily as one striking the rear, and no Federal Motor Vehicle Safety Standard currently requires a guard to stop it. NHTSA opened a formal review of a possible side-guard mandate in 2023 and estimated that equipping trailers with them could add $3,740 or more in cost per trailer, plus 450 to 800 pounds of weight, figures the trucking industry has cited in pushing back on the idea. That review is still open as of early 2026, per the agency's own regulatory filings, with staff working through the public comments it drew.

The new guide is titled "Underride Truck Accidents in Texas: Why They Are So Deadly and Who Is Liable." The reason sits in basic geometry. A trailer's underside lines up with roughly the height of a car's windshield rather than its bumper. So a car that goes underneath skips past the crumple zone and airbags entirely and hits the frame with the windshield instead. A 2019 Government Accountability Office report on the issue, GAO-19-264, flagged a related problem with the data itself. Standard police crash forms have no dedicated way to mark a crash as an underride, so the government's own numbers likely miss a real share of them.

Figuring out who pays in an underride case rarely stops at the driver. It can, if the driver alone did something careless and everything else checks out. But the guide's own examples usually show the chain running much further than that, often reaching the motor carrier under Texas's respondeat superior doctrine, which holds an employer responsible for a driver's negligence on the job. A carrier may have pushed a schedule hard enough to affect a driver's decisions. A trailer may belong to a leasing company separate from whoever was hauling it that day. A repair shop may have patched a bent guard instead of replacing it. Occasionally, a manufacturer's guard gives way despite passing inspection.

Texas complicates the math further with its proportionate-responsibility rule. A jury splits fault by percentage among everyone involved, including the injured driver, and a finding of more than 50% fault against that driver wipes out the recovery entirely. In a case worth $500,000, for instance, a jury assigning the injured driver 20% of the blame would cut that recovery to $400,000; assign 51%, and it disappears. That's part of why evidence like a trailer's lighting condition and guard placement carries so much weight in these cases; it's often what the fault percentage actually turns on.

None of that evidence lasts long. Repair crews fix guard damage, maintenance replaces worn lighting, and a truck's electronic logging data can be overwritten within days of a crash. On an underride case, the León Law Firm's practice is to move first. That means sending a preservation letter before the trailer goes back into service, inspecting the guard directly, and pulling the truck's electronic data early rather than waiting to see how the insurer responds: https://theleonlawfirm.com/underride-truck-accidents/.

The firm has served Sugar Land since 1995 and works these cases in English and Spanish. Cases go forward on contingency. A family pays nothing upfront to find out whether they have one: https://theleonlawfirm.com/18-wheeler-accident-lawyer/.

About The León Law Firm: Carlos A. León started the firm in Sugar Land in 1995. Three decades later, the firm has recovered more than $100 million for injured clients, including a $13 million verdict in 2023. It represents people across Houston, Harris County, Fort Bend County, and the rest of Texas, in English and Spanish. Cases are handled on contingency, so nothing is owed for attorney's fees or case costs unless money is recovered. The firm has been named to Texas Super Lawyers every year from 2021 through 2025. More information: https://theleonlawfirm.com/about-law-firm/. Past results don't guarantee a future outcome; every case is different.

Contact Info:
Name: Carlos Leon
Email: Send Email
Organization: The León Law Firm, P.C.
Address: 1 Sugar Creek Center Boulevard, Sugar Land, TX 77478, United States
Website: https://theleonlawfirm.com

Source: NewsNetwork

Release ID: 89203758

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