FMCSA Hours of Service Violations in Truck Accident Cases

Fatigued truck driving remains one of the most dangerous and most preventable causes of serious highway crashes in Missouri. Federal law strictly limits how many hours a commercial truck driver may spend behind the wheel before resting, and every commercial truck on the road today generates a digital record of whether the driver followed those limits. For Missourians injured in a commercial truck accident, that digital record, the Electronic Logging Device data, is often the single most powerful piece of evidence in the case, but only if it is preserved before the trucking company’s routine data cycles erase it.

What the FMCSA Hours of Service Rules Require

The Federal Motor Carrier Safety Administration regulates how long commercial drivers can operate under the Hours of Service rules found in 49 CFR Part 395. For property carrying drivers, the rules impose several limits that must all be satisfied at the same time.

The 11 hour driving limit allows a driver to drive a maximum of 11 hours after taking 10 consecutive hours off duty. Once those 11 hours of actual driving time are used, the driver cannot get back behind the wheel until another full 10 hour rest period is completed.

The 14 hour window limits the total span of time in which that driving must occur. The clock starts the moment a driver begins any on duty work, not just driving, and it keeps running through loading, fueling, paperwork, and delays at a shipper or receiver. A driver cannot drive past the 14th consecutive hour after coming on duty, even if some of that time was spent waiting rather than driving, and even if the driver has not yet used the full 11 hours of allowable driving time.

The 30 Minute Break Rule

The 30 minute break rule requires a driver to take a break of at least 30 minutes after 8 cumulative hours of driving time, before continuing to drive.

The 60/70 hour limit caps total on duty time over a rolling period. A driver operating for a carrier that runs vehicles every day of the week cannot go on duty more than 70 hours in any 8 consecutive days, and drivers for carriers that do not operate every day are capped at 60 hours in 7 consecutive days. A driver can reset this weekly clock only by taking 34 consecutive hours off duty.

These limits were designed by FMCSA to prevent driver fatigue, which research consistently identifies as a significant factor in commercial vehicle crashes. When a driver or a trucking company allows any one of these limits to be exceeded, the result is a Hours of Service violation, and often, a fatigued driver operating an 80,000 pound vehicle among ordinary passenger traffic.

How Electronic Logging Devices Track Compliance

Since the federal ELD mandate took effect, most commercial trucks operating in interstate commerce have been required to use Electronic Logging Devices that automatically record a driver’s duty status. Unlike the old paper logbooks that drivers filled out by hand and that were notoriously easy to falsify, ELDs connect directly to the truck’s engine and record driving time based on when the vehicle is actually in motion. The device captures date, time, location, engine hours, vehicle miles, and identifying information for the driver and the motor carrier, creating a detailed, time stamped record of exactly when a driver was driving, on duty but not driving, in the sleeper berth, or off duty.

This automated record makes it far more difficult for a driver or carrier to disguise a Hours of Service violation after the fact. Where a paper log could simply be filled out to show compliant hours regardless of what actually happened, an ELD’s data is generated by the vehicle itself in real time. When a driver has clearly been driving longer than the log reflects, discrepancies between the ELD data and other records, such as fuel receipts, dispatch records, weigh station timestamps, or toll records, can expose falsified entries.

How Hours of Service Violations Become Evidence in a Crash Case

When a commercial truck is involved in a crash that injures a Missouri driver or passenger, the trucking company’s compliance with the Hours of Service rules becomes a central question in determining liability. If a driver was behind the wheel after the 11 hour limit, driving beyond the 14 hour window, or operating without the required rest, that violation is powerful evidence supporting a claim that the driver’s fatigue caused or contributed to the crash.

ELD records typically show the driver’s complete duty status history for the days surrounding the crash, allowing an attorney to reconstruct precisely how many hours the driver had been on duty, how much rest the driver had actually taken, and whether the carrier’s own dispatch pressures may have encouraged the driver to push past legal limits. This data can corroborate or contradict the driver’s own account of the hours leading up to the crash, and it can reveal whether the trucking company had reason to know its driver was operating in violation of federal safety rules.

Beyond the ELD itself, a truck’s engine control module, sometimes called the black box, can capture additional data such as speed, braking, and throttle position in the moments before a crash. Together, ELD records and ECM data create a detailed, largely objective picture of what the driver was doing and how long the driver had been working, a picture that is difficult for a trucking company’s insurer to argue away with witness testimony alone.

Why This Evidence Disappears Quickly

The evidentiary value of ELD data is enormous, but only if it survives long enough to be used. Federal regulations require motor carriers to retain ELD records of duty status for a minimum of six months. After that window closes, carriers are permitted to destroy the data as part of routine business practices, and many do exactly that on a rolling basis. Other related evidence can disappear even faster. Dash camera footage on some systems overwrites within days. Engine control module data can be lost entirely if the truck is repaired, scrapped, or its systems are reset.

This creates a narrow and unforgiving timeline for injured Missourians and their attorneys. Unlike the years long deadline to file a personal injury lawsuit, the practical deadline to secure this evidence is measured in days and months, not years. Once the data is gone, it is gone permanently, and a case that could have been proven with objective electronic records is left to rely on conflicting witness accounts and the trucking company’s own version of events.

How a Truck Accident Attorney Can Help Preserve the Evidence Before It Is Lost

The standard tool for protecting this evidence is a preservation letter, sometimes called a spoliation letter or litigation hold notice, sent to the trucking company, its insurer, and any relevant third parties as soon as possible after a crash. This letter identifies the crash and formally demands that the carrier preserve all ELD records, engine control module data, dispatch records, driver qualification files, and any onboard camera footage, and that it suspend any routine data destruction policies that might otherwise apply.

Once a carrier receives a proper preservation demand, destroying the requested evidence can expose the company to spoliation sanctions in later litigation, including the possibility that a court allows a jury to assume the destroyed evidence would have been unfavorable to the carrier. This is why early action matters so much. A trucking company has no independent obligation to safeguard evidence indefinitely on its own initiative, and by the time many injured people first speak with an attorney, weeks may have already passed since the crash.

Why Truck Crashes Demand a Different Approach Than Ordinary Car Accidents

Missouri sees a substantial volume of serious commercial vehicle crashes each year. According to data reported by the Missouri Department of Transportation, fatalities involving commercial motor vehicles rose in 2024, increasing by 22 compared to the prior year and pushing the fatality rate involving commercial vehicles from 1.13 to 1.30 per 100 million commercial vehicle miles traveled, missing the state’s safety target for the year. Major interstate corridors converging on the St. Louis region, including I-70, I-44, and I-55, carry heavy commercial truck traffic every day, and fatigue related driving remains a persistent contributing factor across these crashes.

Because the evidence in a trucking case is time sensitive in a way that ordinary passenger vehicle accidents typically are not, Missourians injured in a crash with a commercial truck benefit from moving quickly. Identifying the motor carrier’s USDOT number from the police report, contacting an attorney promptly, and ensuring a preservation letter goes out before routine data cycles run their course can be the difference between a case built on objective electronic proof of a Hours of Service violation and a case built on little more than competing stories about what happened.

If you or a loved one has been injured in a crash involving a commercial truck, understanding how quickly this evidence can vanish is critical to protecting your right to full and fair compensation.