A loaded tractor-trailer can legally weigh 80,000 pounds. Your car weighs about 4,000. When that math goes wrong on I-70 or I-44, the people in the smaller vehicle take the worst of it.

Here is what most victims never learn. The federal government wrote a detailed safety rulebook for the trucking industry. It covers how long a driver may stay behind the wheel, when the carrier must test for drugs, how often brakes get inspected, and how cargo must be tied down. When a carrier or driver breaks one of those rules and someone gets hurt, the violation can do real work in a Missouri courtroom. It can prove fault.

This guide walks you through the rules that matter most after a Missouri truck crash, explains how a violation becomes legal proof, and tells you what to do now. Some of the evidence that wins these cases can be legally destroyed six months after the wreck, so the timing matters more than most people realize.

The federal rulebook covers nearly every commercial truck on Missouri roads

The Federal Motor Carrier Safety Administration (FMCSA) writes the Federal Motor Carrier Safety Regulations, published in Title 49 of the Code of Federal Regulations. These rules bind interstate motor carriers — the trucks hauling freight across state lines on routes like I-70, I-44, I-55, and I-270.

Missouri applies the same federal safety rules to carriers that operate only inside the state. So the regulations in this guide govern nearly every commercial truck you share the road with, whether it crossed three states to reach St. Louis or never left Missouri.

One honest limit. These rules cover commercial motor vehicles and their carriers, not every large vehicle on the highway. Whether a specific regulation covers a specific truck is a question your attorney answers with the carrier's USDOT registration, the driver's logs, and the trip records. Don't assume the answer — verify it.

Hours-of-service rules cap how long a trucker can drive

Fatigue is one of the most common and most preventable factors in truck crashes. The hours-of-service rules in 49 CFR Part 395 attack it directly. For property-carrying drivers, the core limits are:

11-hour driving limit. After 10 consecutive hours off duty, a driver may drive at most 11 hours.
14-hour window. All driving must fit inside 14 hours after the driver comes on duty. Breaks don't pause the clock.
30-minute break. A driver must take 30 minutes off after 8 cumulative hours of driving.
60/70-hour weekly cap. A driver may not drive after 60 hours on duty in 7 days, or 70 hours in 8 days.

These are federal law, not guidelines. A carrier that pressures a driver to beat a schedule, or a driver who fudges the log to squeeze in extra miles, breaks rules written in response to real highway deaths.

Since December 2017, most trucks must record driving time with an electronic logging device (ELD) wired to the engine. The ELD mandate ended the era of the paper logbook that drivers jokingly called a "comic book." If a driver was over hours at the moment of your crash, the ELD data usually proves it.

Know the exceptions, because the defense will raise them. Short-haul drivers operating near their home terminal may be exempt from the 30-minute break and from ELD use entirely. A driver facing unexpected snow or fog may extend driving time by up to two hours under the adverse-driving-conditions rule. An over-hours log is not automatically a violation — the records decide the question.

Here is the part that should worry you. Under 49 CFR § 395.8(k)(1), a carrier must keep records of duty status and supporting documents for only six months. After that, the carrier may lawfully destroy them. The ELD data that could win your case has a built-in expiration date.

Federal law requires drug and alcohol testing — but not after every crash

The FMCSA's testing program under 49 CFR Part 382 requires carriers to test drivers at six points: before hiring, at random through the year, after certain accidents, on reasonable suspicion, before returning to duty after a positive test, and on follow-up after return.

Post-accident testing has precise triggers, spelled out in 49 CFR § 382.303. The carrier must test the driver after any crash involving a death. For a crash involving injury treated away from the scene or tow-away damage, testing is required only if the driver also receives a citation. So the absence of a post-accident drug test does not, by itself, prove the carrier broke the rules. Your attorney checks the citation and the tow records before drawing that conclusion.

The FMCSA also runs the Drug and Alcohol Clearinghouse, a national database of positive tests and refusals. Carriers must query it before hiring a driver and at least once a year for every current driver. A carrier that hired a driver with an unresolved positive test in the Clearinghouse ignored a warning the federal government put in its hands. That failure can support a negligent-hiring claim on top of the crash itself.

Carriers must keep their trucks safe to operate

Brakes that stop 80,000 pounds wear out. Tires carrying heavy loads across thousands of miles fail. Part 396 of the federal rules puts the maintenance duty squarely on the carrier.

The core obligations:

Systematic maintenance. Section 396.3 requires every carrier to systematically inspect, repair, and maintain every vehicle under its control. "We didn't know" is not a defense to a program the carrier never ran.
Driver inspection reports. Section 396.11 requires drivers to inspect the truck and report defects in writing after each day's driving.
Annual inspection. Section 396.17 requires a comprehensive annual inspection covering brakes, steering, suspension, tires, and coupling devices.

When a brake failure or blowout causes a crash, the maintenance records tell the story. A stack of driver reports flagging worn brakes, ignored by the carrier, turns a mechanical failure into a corporate decision. Our firm has seen how this evidence changes a case; in one truck accident claim, the carrier's own records did more to prove fault than any witness.

Carriers must vet the drivers they put behind the wheel

Not everyone may drive an 80,000-pound truck at highway speed. Part 391 sets minimum qualifications: at least 21 years old for interstate driving, a valid commercial driver's license, a current medical examiner's certificate, and a documented road test or equivalent.

The carrier must also build a driver qualification file for every driver. That file includes the driver's employment history for the past three years and an annual review of the driver's record. A carrier that skips this work puts an unknown risk on the road beside your family.

When the file is incomplete, expired, or never checked, the carrier's failure becomes its own claim. Lawyers call it negligent hiring or negligent retention, and it matters for a practical reason: it keeps the focus on the company's choices, not just the driver's mistake in the seconds before impact.

Federal rules also govern cargo and insurance

Two more parts of the rulebook come up constantly in Missouri truck cases.

Cargo securement (Part 393). Freight must be tied down to specific standards — a minimum number and strength of tiedowns, with special rules for coils, lumber, machinery, and containers. A load that shifts can roll a trailer across your lane. A load that falls becomes a projectile at highway speed.

Insurance minimums (Part 387). Because truck crashes cause catastrophic harm, carriers must carry more insurance than ordinary drivers. The federal floor is $750,000 for general freight, up to $5 million for hazardous materials and for buses carrying 15 or more passengers. Those are floors, not ceilings. Many carriers layer primary, excess, and umbrella policies, and finding every layer is part of valuing your claim. Our firm's $877,000 underinsured motorist settlement turned on exactly that kind of coverage mapping.

A violated regulation can prove your Missouri case

Missouri law gives regulation violations real teeth through the doctrine of negligence per se. The idea is simple: when a safety rule defines what careful conduct looks like, breaking that rule is negligence — the jury doesn't have to take the plaintiff's word for what a reasonable carrier would do.

The Missouri Supreme Court applied this doctrine in a truck case four decades ago. In Breeding v. Dodson Trailer Repair, 679 S.W.2d 281 (Mo. banc 1984), a truck with failed brakes rear-ended a stopped driver, and the plaintiff submitted negligence per se based on a brake-equipment safety ordinance. The Court upheld the verdict, quoting Ruediger v. American Bus Lines, 426 S.W.2d 4, 9 (Mo. banc 1967): once the plaintiff proves the violation, the defendant must prove a legal excuse or avoidance for failing to meet the duty the regulation imposed. The burden shifts.

A negligence-per-se claim still has elements. Your attorney must show the carrier violated a specific regulation, that you belong to the class of people the rule protects, that your injury is the kind the rule exists to prevent, and that the violation helped cause the crash. That last point is where the defense fights. An over-hours driver does not automatically cause every crash he is in — the violation must connect to what actually happened.

Expect one more defense move: blame-shifting. Under Missouri's pure comparative-fault system, adopted in Gustafson v. Benda, 661 S.W.2d 11 (Mo. banc 1983), your recovery shrinks by your percentage of fault but never disappears because of it. If a jury values your harm at $500,000 and assigns you 20 percent of the fault, you recover $400,000. The carrier's lawyers will scrutinize your speed, your lane position, and your phone. Proven federal violations keep the jury's attention where it belongs — on the choices that put an unsafe truck or an unfit driver on the road. (One citation note you may see elsewhere: § 537.765 RSMo codifies comparative fault for products-liability cases. In an ordinary truck-crash negligence case, Gustafson is the source of the rule.)

What to do after a truck crash in Missouri

You have five years to file a personal-injury lawsuit under § 516.120, RSMo. Do not let that number comfort you. The lawsuit deadline is five years, but the evidence deadline is six months — the moment a carrier may legally destroy the driver's logs. Act on the shorter clock:

Get medical care immediately, even if you feel lucky. Brain injuries and internal bleeding can hide for days, and a gap in treatment reads as proof you weren't hurt.
Photograph everything — the vehicles, the scene, your injuries. Write down the carrier's name and the USDOT number printed on the truck's door.
Decline recorded statements. The carrier's insurer will call fast, and its job is to shrink your claim. Be polite, say you'll speak through your attorney, and hang up.
Call a truck accident attorney within days, not months. Your attorney sends a spoliation letter — a formal notice demanding the carrier preserve the ELD data, maintenance records, drug-test results, and the driver qualification file. A carrier that destroys evidence after receiving that letter faces court sanctions, which can include the jury being told to assume the destroyed evidence hurt the carrier.
Keep a simple journal of your symptoms, treatment, missed work, and daily limitations. Dated, honest notes carry weight that reconstructed memory never will.

Frequently asked questions about FMCSA rules and Missouri truck crashes

Which FMCSA regulations matter most in a Missouri truck accident case?

Four do the most work: the hours-of-service limits in 49 CFR Part 395 (fatigue), the testing rules in Part 382 (impairment), the maintenance rules in Part 396 (mechanical failure), and the driver-qualification rules in Part 391 (unfit drivers). A proven violation of any of them can establish negligence per se in a Missouri court.

How does a lawyer prove the truck driver was over his hours?

By pulling the ELD data and cross-checking it against dispatch records, GPS pings, toll and fuel receipts, and bills of lading. Falsified logs rarely survive that comparison. But carriers must keep these records for only six months under 49 CFR § 395.8(k)(1), so the preservation letter has to go out early.

Can I recover money if the crash was partly my fault?

Yes. Missouri follows pure comparative fault under Gustafson v. Benda, so your award is reduced by your share of fault but never wiped out by it. Even a driver found 40 percent at fault recovers 60 percent of proven damages.

What is a spoliation letter, and why does it matter so much in truck cases?

It is a formal written notice demanding that the carrier preserve every record tied to the crash — ELD data, maintenance logs, drug-test results, the driver qualification file. Federal rules let carriers destroy logs six months after receipt. Once a spoliation letter arrives, destroying that evidence can bring court sanctions, including an instruction telling the jury to assume the missing records proved the carrier's fault.

How long do I have to file a truck accident lawsuit in Missouri?

Five years from the crash under § 516.120, RSMo. But waiting is a mistake even when the deadline is far off: evidence expires in months, witnesses scatter, and vehicles get repaired. The five-year statute of limitations protects your right to file; only early action protects your ability to prove.

This article is general information about federal trucking regulations and Missouri law. It does not constitute legal advice, and reading it creates no attorney-client relationship. Every case turns on its own facts, and past results do not guarantee future outcomes. If you were hurt in a crash with a commercial truck, talk to a qualified attorney about your situation.

If a truck crash injured you or someone you love, contact Ott Law Firm or call (314) 710-2740 for a free, confidential consultation. The six-month evidence clock is already running.

FMCSA Regulations Every Missouri Truck Accident Victim Should Know