Truck underride accident claims

01 What underride is

That is the whole reason these crashes are treated as their own category. Everything a modern car does to protect the people inside it depends on the collision happening at the height the car was designed for. Underride removes that assumption, which is why the outcomes are so much worse than the speeds alone would suggest.

Many people reading this page will have lost someone. We have written it plainly rather than gently, because the decisions that matter here are practical and some of them are time-limited.

02 Rear guards are required, side guards are not

This asymmetry is the most useful thing on this page, and almost nobody knows it before it affects them.

A rear case can begin with a rule that already existed and ask whether the trailer complied with it. A side case has no such starting point. It has to be built on other ground, which section 06 sets out. Neither is hopeless and neither is straightforward, but they are not the same exercise, and a firm that treats them as interchangeable has not understood the problem.

03 What the rear guard rule requires

The rule is specific about the date, which matters more than people expect on a fleet where trailers stay in service for decades.

The rule also sets requirements for the guard's width, its height above the road, its rear surface and the vertical height of its horizontal member. Those dimensions are why a guard can be present and still fail the standard, and why a competent examination measures rather than merely photographs.

One oddity worth naming, because it will otherwise look like a mistake. This section renders the metric threshold of 4,536 kg as 10,000 pounds. Elsewhere in the same title, the definition of a commercial motor vehicle renders the identical metric figure as 10,001 pounds. We have quoted each section as it reads rather than harmonizing them.

04 The speed the standard was built around, and when it changed

Both figures come from the agency itself rather than from anybody's advocacy, which is what makes them usable. The difference between them is larger than it sounds.

Read that alongside two things: the closing speed in your own case, and the trailer's build date. Section 393.86 requires compliance with the standard in effect when the vehicle was manufactured, so an older trailer is measured against the lower figure and a newer one against the higher. Either way the point survives. A guard doing exactly what was asked of it was scoped, deliberately and explicitly, to a speed that a great many highway collisions exceed. That is not an allegation. It is the agency's own account of why the standards say what they say.

05 The trailers the rule leaves out

Establishing this early avoids months spent on the wrong argument.

An exclusion is not the end of a claim. It removes one route, and it makes the ordinary questions about how the vehicle was being driven, lit, parked and maintained carry more of the weight. Our guide to commercial truck accident claims covers that wider ground.

06 What a side case rests on instead

The absence of a rule cuts both ways, and it is worth understanding why rather than being told the case is weak.

• How the trailer came to be there. A trailer across a roadway during a turn or a reversing maneuver raises questions independent of any guard.
• Conspicuity. Reflective marking, lighting and their condition are separately regulated and are frequently the more productive line.
• What was available. Where equipment existed and was known about, the absence of a mandate is not automatically the end of the question.
• The ordinary case. Speed, positioning, hours, training and maintenance all still apply, and often carry the claim.

A truck underride accident involving the side of a trailer is a harder case to build and a perfectly real one. What it is not is a compliance case, and any assessment that begins by looking for a side guard standard has started in the wrong place.

07 The evidence, and how fast it goes

Photographs taken at the scene are valuable and are not a substitute for the object itself. More truck underride accident claims are weakened by a trailer going back into service than by anything either driver did.

• The guard and its mounting. Dimensions, materials, welds and attachment points, measured rather than described.
• The trailer's identity and age. The build date decides whether the requirement applied to it at all.
• Maintenance and inspection history. Whether damage to the guard had been recorded previously and what was done about it.
• Both vehicles, unrepaired. The crush pattern on the car is how the geometry of the impact gets reconstructed.
• Lighting and reflective marking. Their condition at the time, which deteriorates and gets cleaned or replaced.

08 What to do in the first days

Five steps. If you are managing this on behalf of someone who died, step three is the one that cannot be recovered later.

09 Red flags

The third of those is the one most likely to be technically accurate and still misleading.

One closing thought about a collision of this kind. These are among the few road cases where the physical equipment on the other vehicle is squarely in issue, and where a federal standard, its limits, and its exclusions all bear directly on what happened. That is a great deal of technical ground, and it is not ground anybody should be expected to cover alone while grieving or recovering. A free case review costs nothing, our guide to choosing a truck accident lawyer covers what to look for, and you can read how we match people with attorneys before deciding anything.

Sources and authorities

Everything quoted here is federal regulation or federal rulemaking, and is linked.

On side underride. Our statement that no federal standard requires a side guard rests on the same rulemaking record, which describes a statutory direction to assess the feasibility, benefits and costs of side underride guards and, if warranted, to develop performance standards. An assessment and a possible future standard are not a present requirement. This is an area that has moved before and may move again, so anyone relying on it for a live matter should check the current position.

On the compliance date. The July 2024 date for the upgraded requirement is taken from an official summary of the rule rather than from the compliance provisions of the rule itself, which we did not read in full. It is stated because it bears directly on which standard governs a given trailer, and anyone relying on it for a specific vehicle should confirm it against the rule.

A figure that looks like an error. Section 393.86 renders 4,536 kg as 10,000 pounds. Section 390.5, defining a commercial motor vehicle, renders the same metric figure as 10,001 pounds. We have quoted each as its own section reads and flagged the difference rather than quietly picking one.

What we have left out. We have given no casualty figure, because the federal sources we read this session did not provide one we could state precisely. We have not described the crash-test work published by private research bodies, which is influential in this field but is their copyrighted material rather than public law. And we have not addressed the certification labeling requirement, which has been through rulemaking during 2025 and 2026 and whose current status we did not read in full.

Common questions, answered

General information, not legal advice. What a claim recovers and how long you have are set state by state, so check anything here against your own state and your own attorney.