Most people think truck accidents happen because of mechanical failures, bad weather, or reckless driving. But there’s a quieter, more insidious problem lurking behind thousands of crashes every year: exhaustion.
According to the Federal Motor Carrier Safety Administration’s Large Truck Crash Causation Study, driver fatigue was associated with 13 percent of commercial truck crashes. That might not sound like much until you consider what it means in real terms—hundreds of deaths and thousands of injuries annually from something as preventable as getting enough sleep.
But here’s what makes fatigue so dangerous: unlike drunk driving or speeding, exhaustion is invisible until it’s too late. Below, our friends at Warner & Fitzmartin – Personal Injury Lawyers explain how driver fatigue factors into truck accidents.
Your Brain On Empty
A truck accident lawyer knows that sleep deprivation doesn’t just make you tired. It fundamentally changes how your brain processes information.
According to the Centers for Disease Control and Prevention, being awake for 17 hours produces impairment similar to having a blood alcohol concentration of 0.05 percent. After 24 hours awake, the impairment matches a BAC of 0.10 percent—well above the legal limit of 0.08 percent for drunk driving.
Think about that. A truck driver finishing an extended shift is operating an 80,000-pound vehicle with the same cognitive impairment as someone who’d fail a breathalyzer test. Except there’s no roadside test for fatigue. No officer can pull over a trucker and definitively prove they’re too tired to drive safely.
The CDC found that nearly 5 percent of adult drivers admitted to nodding off at the wheel within the past month. Among commercial drivers who work irregular schedules and long hauls, that number is almost certainly higher.
The Microsleep Problem
One of the most terrifying aspects of fatigue is something called microsleep—brief episodes lasting just a few seconds where the brain essentially shuts down without the person even realizing it.
At highway speeds, a truck travels the length of a football field in just a few seconds. During a microsleep episode, the driver isn’t processing any visual information. They’re not steering. They’re not braking. The truck is essentially driving itself while the person behind the wheel is unconscious.
The AAA Foundation found that 16.5 percent of fatal crashes involve a drowsy driver. But researchers suspect the actual number is much higher because fatigue is difficult to prove after an accident. Unlike alcohol or drugs, exhaustion leaves no measurable trace in blood or tissue samples.
When investigators arrive at a crash scene and find a truck that ran off the road at high speed with no evidence of braking, they suspect fatigue. But proving it requires examining logbooks, interviewing dispatchers, and reconstructing the driver’s schedule over multiple days.
Why Truckers Push Through
Truck drivers don’t stay on the road when they’re exhausted because they’re reckless. They do it because the entire industry is structured around tight deadlines and mileage-based pay.
If a driver stops to rest, they’re not earning money. If they miss a delivery window, they might lose future business. Even with federal hours-of-service regulations limiting driving time to 11 hours per day, drivers often work right up to that limit day after day.
The pressure comes from multiple directions. Shipping companies want freight delivered on schedule. Trucking companies want their equipment in constant use. Drivers want to maximize their income. All these factors combine to create an environment where fatigue becomes normalized.
Research on long-haul truck drivers found they averaged less than five hours of sleep per night during multi-day trips. That’s well below the seven to nine hours adults need to function optimally. The sleep debt compounds over time, making drivers progressively more impaired even when they feel okay.
The Circadian Factor
Human bodies aren’t designed for round-the-clock operation. We have internal clocks that regulate alertness throughout the day, with natural dips in the early morning hours between 2 AM and 6 AM, and again in mid-afternoon.
Truck drivers who work overnight shifts are fighting against millions of years of evolution. Their bodies want to sleep when they’re required to stay alert. No amount of willpower or coffee can override basic biology indefinitely.
The CDC notes that most drowsy driving crashes occur between midnight and 6 AM—exactly when circadian rhythms make people most vulnerable to falling asleep. Trucks running late-night routes are operating during the highest-risk period.
Many drivers also suffer from untreated sleep disorders like sleep apnea, which fragments their rest even when they’re off duty. They go to bed for eight hours but wake up exhausted because they weren’t getting quality sleep. Then they climb back into the truck and drive.
Why Hours-of-service Rules Aren’t Enough
Federal regulations require truck drivers to take a 30-minute break during the first eight hours of their shift and limit driving to 11 hours per day with at least 10 hours off duty. On paper, these rules should prevent fatigue.
In practice, compliance doesn’t guarantee alertness. A driver who spends their off-duty time dealing with personal stress, sleeping in a noisy truck stop, or suffering from a sleep disorder might log the required hours off but still be exhausted.
Electronic logging devices have made it harder to falsify records, but they can’t measure actual sleep or alertness levels. They track when the truck is moving, not whether the person behind the wheel is fit to drive.
Studies have shown that crash risk increases significantly during the eighth through eleventh hours of driving. The FMCSA found that the risk effectively doubles from the eighth to the tenth hour and doubles again from the tenth to the eleventh.
What Evidence Looks Like
When fatigue causes a truck accident, certain patterns emerge. The truck often runs off the road in a straight line at full speed. There are no skid marks showing attempted braking. The driver has no explanation for why they left their lane.
Investigators look at the driver’s logbooks, cell phone records, and work history. They interview the trucking company about scheduling practices. They examine whether the driver was taking medication that could cause drowsiness.
If the driver admits to falling asleep—which happens in about 18 percent of fatigue-related crashes according to research—the case becomes much clearer. But most drivers either don’t realize they experienced microsleep or are reluctant to admit it.
Medical records sometimes reveal untreated sleep disorders. Electronic logging device data might show the driver consistently maximized their allowable hours without taking additional rest. Witness statements might describe erratic driving in the minutes before the crash.
The Bottom Line
Driver fatigue was associated with 13 percent of commercial truck crashes according to the FMCSA’s Large Truck Crash Causation Study, and the CDC reports that being awake for 17 hours produces impairment similar to a blood alcohol concentration of 0.05 percent, while 24 hours awake matches a BAC of 0.10 percent—above the legal driving limit. Microsleep episodes lasting just seconds can cause trucks to travel the length of a football field without any driver input, and these brief lapses often leave no physical evidence after crashes. Research shows long-haul truck drivers averaged less than five hours of sleep per night during multi-day trips, well below the seven to nine hours adults need, with sleep debt compounding over time. If you’ve been injured in a truck accident where the driver may have been fatigued, consider consulting with a qualified attorney who can investigate logbooks, electronic logging device data, and company scheduling practices to determine if exhaustion played a role.