Who Is Liable in an Underride Truck Accident? (Driver vs. Manufacturer)
- 6 hours ago
- 14 min read
This article is for informational purposes only and does not constitute legal advice. Every truck accident case is unique. Consult a licensed personal injury attorney in your state for guidance specific to your situation.
When a passenger car slides beneath the undercarriage of a semi-truck or trailer during a collision, the results are almost always catastrophic. These crashes — known as underride accidents — are among the deadliest and most legally complex truck accidents in the United States. If you or a loved one has been injured in an underride crash, one of the first questions you'll face is: Who is liable in an underride truck accident?
The answer is rarely simple. Depending on the circumstances, liability can fall on the truck driver, the trucking company, the trailer manufacturer, or a combination of all three. Understanding each party's potential legal exposure — and how the law approaches these cases — is critical to protecting your rights.
Table of Contents
What Is an Underride Truck Accident?
An underride truck accident occurs when a smaller passenger vehicle collides with a large commercial truck or trailer and slides underneath it. Because of the significant height difference between an 18-wheeler's trailer and a standard car, the trailer structure does not strike the car's reinforced bumper or crumple zone — it strikes the windshield and passenger cabin directly.
There are two main types:
Rear underride — The most common type. A passenger vehicle crashes into the back of a slow-moving or stopped semi-truck and slides beneath the trailer. This often happens at night, in poor weather, or when a truck stops suddenly without adequate warning lights.
Side underride — A vehicle slides underneath the side of a trailer, typically at intersections during wide turns or when a truck crosses a lane. Side underride accidents often occur at intersections or during wide turns when a truck driver fails to see a smaller car. Both types can occur at relatively low speeds, and both frequently result in death or catastrophic permanent injury.
Why Underride Crashes Are So Deadly
Every modern passenger vehicle is built with crumple zones, reinforced pillars, side-impact airbags, and front airbags. These systems are designed to work together during a collision — absorbing energy, deploying airbags at the moment of impact, and keeping the passenger compartment intact.
Underride accidents bypass virtually every safety feature that modern vehicles provide — airbags do not deploy effectively, crumple zones never engage to absorb impact energy, and seatbelts cannot prevent occupants from striking the trailer structure that has intruded into their space. (Source: LawCounty, https://lawcounty.com/truck-accidents/underride-truck-accident)
The result is a collision where the vehicle's occupants have none of the protection the car was designed to provide. The trailer's frame — which rides well above a car's bumper — shears into the windshield and roof at the exact height of the driver's head.
Underride accidents kill between 200 and 500 Americans every year, with many more suffering catastrophic injuries, including traumatic brain damage, spinal cord injuries, and severe facial trauma. A 2024 study cited during major litigation found at least 14,350 known fatalities involving rear underride crashes — a figure that likely underestimates the true toll because many crashes are not coded correctly in police reports. (Source: Simon Law PC, https://simonlawpc.com/results/jury-renders-462-million-verdict-to-families-of-victims-of-fatal-truck-underride-crash/)
The tragedy compounds when you understand that many underride deaths are preventable with proper safety equipment — guards specifically designed to stop vehicles from sliding beneath trailers. The technology exists. The question of who is liable in an underride truck accident often comes down to who failed to use it.
Federal Regulations Governing Underride Guards
Rear underride guards — also called rear impact guards (RIGs) — have been federally required on trailers since the late 1990s, following a 1967 crash that killed actress Jayne Mansfield. As of 2025, the same weak 1998 standards remain in effect, despite clear evidence that they are inadequate, and the regulatory process has moved at a glacial pace while hundreds continue to die annually in preventable crashes. (Source: Martin Wren Law, https://martinwrenlaw.com/blog/underride-trucking-accidents-virginia/)
In 2022, NHTSA issued an updated final rule under the Bipartisan Infrastructure Law. The rule upgrades requirements for rear underride protection, requiring rear impact guards to withstand impacts at 56 km/h (35 mph), up from the previous standard of 30 mph. The rule amends FMVSS No. 223 and FMVSS No. 224, governing strength and installation of RIGs on new trailers. (Source: Federal Register, https://www.federalregister.gov/documents/2022/07/15/2022-14330/federal-motor-vehicle-safety-standards-rear-impact-guards-rear-impact-protection)
The federal government also started requiring underride guards to be checked as part of the required annual inspection, with FMCSA amending the Federal Motor Carrier Safety Regulations to include rear impact guards on the list of items that must be examined. (Source: Trucking Info, https://www.truckinginfo.com/10176166/nhtsa-issues-new-underride-guard-rules)
As for side underride guards, the situation is dramatically different. NHTSA floated a possible side underride mandate with an Advance Notice of Proposed Rulemaking in 2023, but no further action has been taken by the agency since, with a January 2026 timeline set only for analyzing comments. (Source: Commercial Carrier Journal, https://www.ccjdigital.com/regulations/article/15816526/legislation-to-mandate-side-underride-guards-reintroduced)
Legislation called the Stop Underrides Act 2.0 was reintroduced in Congress in early 2026 to mandate side guards on new trailers. NHTSA estimated potential additional costs of a mandate at $3,740 or more per trailer in equipment and installation alone, plus between 450 and 800 additional pounds. (Source: Overdrive, https://www.overdriveonline.com/regulations/article/15816475/congress-eyes-trailer-side-underride-guard-mandate) Industry groups have resisted the mandate, calling it costly — but safety advocates point out that side guards cost roughly $3,500 per trailer and can prevent catastrophic deaths.
The gap between what regulations require and what safety experts say is needed is at the heart of many underride liability cases.
When Is the Truck Driver Liable?
The truck driver is often the first party investigated in an underride accident. While not every crash is the driver's fault, driver negligence is a frequent contributing factor.
Failure to use lights, reflectors, or warning triangles. Federal regulations require truckers who stop on a roadway to immediately activate hazard flashers and place warning triangles within specific distances behind the vehicle. A driver who stops on a highway shoulder or travel lane without proper warnings creates a hidden obstacle for approaching traffic.
Sudden or unsafe braking. A truck that makes an abrupt stop can leave trailing vehicles with insufficient time to react, leading to rear underride collisions. If that sudden stop was unnecessary or violated safe following distance rules, the driver's negligence contributed to the crash. (Source: Bruning Legal, https://www.bruninglegal.com/blog/underride-accidents-causes-liability-and-legal-remedies/)
Improper turns. Side underride collisions frequently occur when a truck driver makes a wide turn across traffic without ensuring the path is clear. If a truck driver allows a truck to make a U-turn in an unsafe area, they can be responsible, blocking traffic and placing oncoming vehicles at risk for exactly this type of crash. (Source: Martin Wren Law)
Distracted or fatigued driving. A driver operating beyond federally mandated hours-of-service limits, or distracted by a phone or navigation system, may fail to respond to hazards in time. Fatigued driving is a recognized category of driver liability in underride cases. (Source: Bruning Legal)
Missing or non-functional lights. Trucks are required to have functioning tail lights, brake lights, and reflective conspicuity tape. A driver who knowingly operates a vehicle with broken lighting bears personal responsibility for any collision that results.
When a truck driver is an employee (not an independent contractor), the trucking company is automatically liable for the driver's on-duty negligence under a legal doctrine called respondeat superior — meaning the employer answers for the employee's conduct. This is almost always one of the first arguments your truck accident attorney will assert.
When Is the Trucking Company Liable?
Even when a crash is caused primarily by driver negligence, the trucking company almost always faces independent liability. There are multiple legal theories under which a carrier can be held responsible.
Respondeat superior (vicarious liability). Trucking companies are automatically liable for the negligent acts of their employed drivers committed within the scope of employment.
Negligent maintenance. Trucking companies can be held liable for failing to properly maintain their fleet or neglecting to install adequate safety equipment. A carrier that allows rear impact guards to corrode, crack, or become misaligned without repairs is creating conditions that turn a survivable collision into a fatal one. (Source: Caroselli Beachler Coleman, https://www.cbmclaw.com/truck-underride-guards-the-critical-safety-feature-missing-in-many-pittsburgh-trucking-accidents/)
Choice not to upgrade. Federal minimums are the floor, not the ceiling. If a trucking company chose not to install underride guards exceeding federal minimums — even when more effective guards were available at reasonable cost — that choice may constitute negligence. (Source: LawCounty)
Negligent hiring and training. If a company hired a driver with a documented history of violations, prior accidents, or license suspensions, and failed to screen those records, the company can be held independently liable.
Hours-of-service pressure. A carrier that pressures drivers to skip required rest breaks or falsify logbooks — creating conditions for fatigued driving — carries its own liability separate from the driver's.
Trucking companies typically carry commercial insurance policies in the range of $750,000 to several million dollars. In catastrophic underride cases, pursuing the carrier aggressively — not just the driver — is essential to securing full compensation.
When Is the Trailer Manufacturer Liable?
This is the area of underride litigation that has seen the most dramatic legal development in recent years — and it is where product liability law comes into direct conflict with federal minimum standards.
The core product liability theory. Trailer manufacturers may be liable under product liability theories if their underride guards were defectively designed or failed to perform as reasonably expected. Designing and selling trailers with inadequate underride protection, when better designs exist and are economically feasible, may constitute a defective and unreasonably dangerous product. (Source: LawCounty)
Compliance with federal standards is NOT a complete defense. Meeting minimum federal requirements does not automatically shield a manufacturer from liability. Courts have allowed juries to find manufacturers liable even when their guards technically complied with FMVSS No. 223.
In the Wabash National case, the trailer manufacturer maintained that it complied with federal safety standards. Jurors heard testimony that a rear impact guard with four protective posts instead of an older two-post design would have prevented the fatal underride. The plaintiff's legal team argued that Wabash never performed effective crash testing on the two-post guard despite using it for nearly 30 years. (Source: CVN, https://blog.cvn.com/breaking-462m-verdict-returned-in-trial-over-trucks-rear-impact-guard-design-watch-full-trial-via-cvn)
Failed guard equals product defect. If an underride guard was installed but failed during the crash due to a design or manufacturing defect, the company that made the guard could be held responsible. This includes situations where a guard crumpled or deformed in a way that allowed underride at speeds the guard was supposed to prevent. (Source: Caroselli Beachler Coleman)
Side underride and the no-guard theory. On trailers with no side underride protection, manufacturers face the argument that the absence of side guards — where side guards are technically and economically feasible — constitutes a defective design. (Source: Martin Wren Law)
If you believe a guard failure or an absent guard contributed to your injuries, a truck accident lawyer with experience in product liability litigation is essential. These cases require engineering experts, access to the manufacturer's crash testing records, and the ability to challenge federal-compliance defenses.
The $462 Million Verdict That Changed the Industry
In 2024, a St. Louis jury delivered what may be the most significant underride verdict in American legal history. The jury found trailer manufacturer Wabash National Corporation responsible for the deaths of two young fathers killed when their car went underneath the rear of a trailer, returning a verdict of $462 million. (Source: Simon Law PC, https://simonlawpc.com/results/jury-renders-462-million-verdict-to-families-of-victims-of-fatal-truck-underride-crash/)
The accident occurred when their vehicle slid beneath a tractor-trailer that had slowed down for traffic on Interstate 55 near an exit in downtown St. Louis. Taron Tailor, 30, and Nicholas Perkins, 23, both died instantly. Perkins left behind a 2-year-old daughter, and Tailor's wife was pregnant at the time of the accident. (Source: Bradley Law, https://thebradleylawfirm.com/blog/st-louis-jury-slams-tractor-trailer-manufacturer-for-deaths-despite-meeting-minimum-federal-standards/)
The plaintiffs successfully argued that trucking industry leaders have been at the forefront of lobbying efforts to prevent federal regulations from requiring rear impact guards to be made to prevent underride at survivable speeds. The case sent a direct message: jury sympathy for industry compliance arguments has limits. This verdict has potentially industry-wide implications and may accelerate voluntary improvements in rear guard design even without new federal regulation.
Multiple Defendants: How Shared Liability Works
One of the features that makes underride cases especially complex is that liability is rarely binary. A single crash can generate valid claims against the driver, the carrier, and the manufacturer simultaneously.
Consider a scenario where: a fatigued driver stops in a travel lane without warning triangles (driver negligence); the carrier failed to fix a cracked rear impact guard flagged in the last annual inspection (carrier negligence); and the guard's design was insufficient to arrest an underride at 40 mph even in good condition (manufacturer product liability). All three failures contributed to the outcome. All three parties can be named as defendants.
This multi-defendant structure benefits victims in an important way: it creates multiple pools of insurance coverage. A commercial carrier's policy, plus a manufacturer's products liability coverage, can together provide far more compensation than a single defendant could. Each defendant may try to shift blame to the others — an experienced legal team coordinates evidence to counter each deflection and hold all parties accountable.
Comparative Negligence and Underride Claims
In some underride crashes, questions arise about whether the driver of the passenger vehicle contributed to the collision. Was the car traveling at excessive speed? Did the driver fail to maintain a safe following distance? Was the driver distracted?
Most states apply comparative negligence rules, which allow a victim to recover damages even if they were partially at fault, with the compensation reduced proportionally to their degree of fault. For example, if a jury finds the victim was 20% responsible for a $1 million case, the victim recovers $800,000. A small number of states still use contributory negligence, which bars recovery entirely if the victim contributed in any way.
Defendants in underride cases routinely deploy accident reconstruction experts to argue that the victim's vehicle was speeding or following too closely. Countering this requires independent reconstruction experts, black box data from both vehicles, and careful analysis of road and weather conditions. Do not accept fault assignment from insurance adjusters without independent legal review.
What Evidence Is Critical in Underride Cases?
Evidence in underride crash cases deteriorates quickly. The truck may be repaired or replaced. Electronic logs may be overwritten. The most valuable evidence must be preserved immediately.
The truck and trailer itself. The condition of the rear or side underride guard at the time of the crash is central to both carrier negligence and manufacturer product liability claims. Physical inspection — ideally before the trailer is repaired — is essential.
Event data recorder (EDR) / black box data. Commercial trucks are equipped with electronic logging devices (ELDs) and event data recorders that capture speed, braking patterns, and hours of service. This data is typically only stored for a short window and can be overwritten.
Driver logs and hours-of-service records. Evidence of fatigue — specifically, a driver who has exceeded federal driving limits — is powerful proof of negligence.
Maintenance and inspection records. Any prior flag of damage to the underride guard, lighting systems, or reflective tape is direct evidence of carrier negligence.
Manufacturer crash testing records. In product liability cases, internal engineering files, crash test data, and communications about known guard failures can be obtained through discovery. These records were critical in the Wabash National verdict.
Send a spoliation letter. An attorney can send a formal legal demand requiring all parties to preserve evidence immediately. Failure to preserve evidence after receiving such a letter can result in sanctions and adverse jury instructions at trial.
The sooner you contact legal counsel after an underride crash, the better your chances of preserving the evidence that determines liability. Contact us today for a free case evaluation — there is no fee unless you recover.
How Underride Accident Compensation Is Calculated
Underride crashes produce some of the most severe injury outcomes in all of personal injury law. Compensation in these cases reflects that severity.
Economic damages include all verifiable financial losses: past and future medical expenses, lost wages and diminished earning capacity, cost of home modifications for disability, and long-term care costs.
Non-economic damages compensate for harms that do not appear on a bill: pain and suffering, loss of enjoyment of life, disfigurement, emotional distress, and loss of consortium.
Punitive damages are available in cases involving reckless or intentional misconduct. The Wabash National verdict's $450 million in punitive damages illustrates what juries are willing to award when they conclude a defendant knowingly chose profit over safety.
Cases involving underride fatalities or catastrophic injuries frequently result in settlements exceeding $1 million when liability is properly established. In wrongful death cases, surviving family members may pursue compensation for funeral costs, loss of financial support, and loss of companionship.
If you have lost a loved one in an underride crash, you deserve to understand the full scope of what the law allows you to recover. Contact our team for a confidential consultation.
FAQ
What is an underride truck accident?
An underride truck accident occurs when a smaller passenger vehicle collides with a commercial truck or trailer and slides underneath it. Because the trailer rides significantly higher than a car's front bumper, the impact bypasses the car's crumple zones and airbags and strikes the passenger compartment directly, often causing fatal or catastrophic injuries.
Who is usually at fault in an underride truck crash?
Fault depends on the specific circumstances. The truck driver may be at fault for negligent operation, such as improper stops, inadequate lighting, or unsafe turns. The trucking company may be liable for maintenance failures or negligent hiring. The trailer manufacturer may face product liability claims if the underride guard was defectively designed or failed. In many cases, more than one party shares fault.
Can a trailer manufacturer be sued even if they met federal safety standards?
Yes. Federal minimum standards establish a floor, not a ceiling. Courts have allowed juries to find manufacturers liable even when their trailers technically complied with FMVSS No. 223 if the manufacturer knew the guard design was insufficient, failed to conduct adequate crash testing, or chose not to adopt a safer design that was technically and economically feasible.
Are side underride guards required by federal law?
Currently, no. Federal regulations require rear underride guards on new trailers above 10,000 lbs GVWR, but there is no federal mandate for side underride guards as of 2026. Legislation known as the Stop Underrides Act 2.0 was reintroduced in Congress in early 2026 to address this gap, but has not yet passed.
What should I do immediately after an underride truck accident?
Seek medical attention first. As soon as possible, contact a commercial truck accident attorney to preserve critical evidence — including the truck's black box data, driver logs, maintenance records, and the condition of the underride guard. Send a spoliation letter through your attorney demanding evidence preservation. Do not give recorded statements to insurance adjusters before speaking with legal counsel.
How long do I have to file a lawsuit after an underride crash?
Statutes of limitations vary by state, generally ranging from one to three years from the date of injury or death. Acting quickly is critical because evidence deteriorates, witnesses' memories fade, and electronic records can be legally overwritten if not preserved early.
What is the difference between rear and side underride accidents?
Rear underride accidents occur when a vehicle crashes into the back of a trailer. Side underride accidents occur when a vehicle slides under the side of a trailer, often at intersections during wide turns. Side underride accidents are especially dangerous because federal regulations do not currently require side guards, leaving a major gap in occupant protection.
Can the victim's own negligence reduce their compensation?
Yes. Most states follow comparative negligence rules that allow recovery even if the victim was partly at fault, but reduce the award proportionally. A small number of states use contributory negligence, which can bar recovery entirely if the victim contributed at all. An attorney can assess how your state's rules apply to your specific case.
How much is an underride truck accident case worth?
Every case is different, but underride crashes frequently produce the most severe injuries in all of truck accident litigation. Settlements and verdicts involving death or permanent catastrophic injury regularly exceed $1 million. The largest verdicts — including a $462 million jury award in 2024 — reflect cases where juries concluded a manufacturer acted with reckless disregard for human safety.
Get Legal Help for an Underride Truck Accident
Determining who is liable in an underride truck accident requires a thorough investigation, access to engineering experts, and the legal experience to pursue multiple defendants simultaneously. Trucking companies and trailer manufacturers have aggressive legal teams working to minimize their exposure the moment a crash occurs.
Contact us today for a free, confidential legal consultation. There is no fee unless you recover.
References
LawCounty — Underride Truck Accidents: The Deadliest Type of Truck Crash
Banks & Jones — Catastrophic Injuries from Truck Underride Accidents
Bruning Legal — Underride Accidents: Causes, Liability, and Legal Remedies
Caroselli Beachler Coleman — Truck Underride Guards: The Critical Safety Feature
NHTSA — Comprehensive Actions to Increase Underride Protection on Truck Trailers
Federal Register — FMVSS Rear Impact Guards, Rear Impact Protection Final Rule
Commercial Carrier Journal — Legislation to Mandate Side Underride Guards Reintroduced
Overdrive — Congress Eyes Trailer Side Underride Guard Mandate
Simon Law PC — Jury Renders $462 Million Verdict in Fatal Truck Underride Crash
CVN — $462M Verdict Returned in Trial Over Truck's Rear Impact Guard Design
Editorial Standards & Review
This article was researched and written in accordance with pilawnews.com’s Zero-Hallucination Policy. All statistics are drawn from verified, publicly accessible government sources (FMCSA, NHTSA, IIHS) or documented legal and news publications. No settlement figures, case outcomes, or legal conclusions have been fabricated or presented without source verification. Readers should consult an attorney licensed in their state for jurisdiction-specific guidance.