Most people would never drive after several drinks. Far fewer think twice about driving after a short night's sleep, a long workday, or six hours on the road with one more to go.
That gap matters this time of year. Holiday travel stacks long drives, early darkness, and late returns on top of each other, and fatigue is one of the risks that is hardest to see in yourself.
The numbers are probably much higher than reported
NHTSA counts 644 deaths in drowsy-driving-related crashes in 2024. The agency itself says its figures are an underestimate, because drowsiness is hard to identify after a crash. There is no breath test for being tired, and drivers who fell asleep often cannot or will not say so.
Researchers have tried to estimate the real number in other ways. The AAA Foundation for Traffic Safety, using an in-depth crash investigation approach, estimated that 17.6% of all fatal crashes from 2017 through 2021 involved a drowsy driver, or about 29,834 deaths over those five years.
The Governors Highway Safety Association's 2026 update of its drowsy driving report applied that share to recent federal crash data and arrived at roughly 6,000 deaths a year, about ten times what police-reported data shows.
The precise number is uncertain. The direction is not: fatigue is a much bigger factor on American roads than the official count suggests.
How little sleep it takes
A 2016 AAA Foundation study compared drivers' crash rates by how much they had slept in the previous 24 hours. Against drivers who had slept at least seven hours, the crash rate was:
- 1.3 times higher after six to seven hours
- 1.9 times higher after five to six hours
- 4.3 times higher after four to five hours
- 11.5 times higher after less than four hours
The night before a holiday trip is often exactly when people sleep the least: packing, finishing work, getting kids settled, and setting an early alarm to beat traffic.
Why fatigue and wrong-way risk overlap
Fatigue does not cause most wrong-way crashes. Impairment does; ADOT reports that two out of three wrong-way crashes are caused by impaired drivers.
But the two problems share the same hours and the same weaknesses. NHTSA identifies midnight to 6 a.m. and the late afternoon as the times when sleepiness peaks. ADOT reports that three out of four wrong-way crashes happen between 6 p.m. and 6 a.m., and one-third between midnight and 3 a.m.
A tired driver is less able to read an unfamiliar interchange, slower to notice a red WRONG WAY sign, and slower to react to headlights coming the wrong way. Being alert is part of what lets you avoid someone else's mistake.
Warning signs you should not argue with
NHTSA points to crossing over lane lines or hitting a rumble strip as a key sign of drowsiness, especially when driving alone. Other common signs include:
- Frequent yawning or heavy eyelids
- Missing your exit or not remembering the last few miles
- Drifting toward the shoulder or the center line
- Trouble holding a steady speed
If you notice any of these, the decision has already been made for you. It is time to stop.
What actually helps, and what doesn't
Sleep before the trip. NHTSA notes that experts recommend seven to eight hours of sleep a night. The AAA Foundation data suggests that the last hour or two of sleep you skip costs more than people expect.
Avoid the peak sleepiness hours when you can. Plan departures and arrivals so you are not on the road between midnight and 6 a.m.
Pull over for a short nap. NHTSA suggests that if you feel sleepy, one to two cups of coffee and a 20-minute nap in a safe place, such as a lighted, designated rest stop, can help. The benefit is temporary, so treat it as a way to reach a real stopping point, not to drive all night.
Do not rely on tricks. NHTSA warns that coffee or energy drinks alone are not always enough, and that sleepy drivers can experience brief losses of consciousness lasting four or five seconds. Cold air and loud music do not change that.
Share the driving. On long trips, switch drivers before the current driver is exhausted, not after.
Check your medications. NHTSA advises reading labels for drowsiness warnings. Cold and allergy medicines are common in the holiday season and some can cause drowsiness.
Skip alcohol entirely before driving. Even a small amount adds to fatigue.
Plan the return trip, too
Holiday weekends tend to end with a long drive home on Sunday, after several nights of short sleep and big meals. That return trip is often more dangerous than the trip out.
Build in a realistic stopping point. Know where you could get a room if you fall behind. Decide in advance that if anyone in the car is fading and no one else can drive, the trip stops for the night.
The habit worth keeping
NMWWD is a Phoenix-based nonprofit working to prevent wrong-way crashes. Most of our work focuses on impaired driving and the conditions where wrong-way entries happen. Fatigue belongs in that conversation because the same habits protect against both: drive rested, avoid the overnight hours, and stop when your body tells you to.
If you would like to help us bring these basics to more Arizona drivers this holiday season, get involved or support our work.
Sources: NHTSA — Drowsy Driving · AAA Foundation for Traffic Safety — Drowsy Driving in Fatal Crashes, United States, 2017–2021 · AAA Foundation for Traffic Safety — Acute Sleep Deprivation and Risk of Motor Vehicle Crash Involvement · GHSA — Wake Up Call 2026 Update · Arizona Department of Transportation — Wrong-Way Drivers