Work driving fatigue: safer shifts, schedules and trip rules for employers
How night shifts, overtime and tight schedules raise crash risk and how to manage fatigue
Picture a utility technician finishing an emergency callout at 3 a.m. after a full day shift. The work is done. The last task is a 45 minute drive home on empty roads. No rule was broken. Yet fatigue scientists would rate that drive as one of the riskiest moments of the week.
Driving is one of the deadliest parts of many jobs. In 2024, transportation incidents caused 1,937 of the 5,070 U.S. work deaths (38.2%). Roadway crashes killed 1,146 workers [1]. Those counts exclude deaths during a normal commute [2]. So the drive home after a long shift barely shows up in work injury data.
This guide takes a fatigue researcher’s and fleet safety manager’s view of how sleep loss, night work, overtime and time pressure build crash risk. It includes a scheduling checklist, trip rules, a supervisor script and incident review questions. For the basics of drowsiness, see our drowsy driving guide.
Sleep and the body clock: the two forces behind fatigue
Fatigue at the wheel has two main sources. One is sleep loss, from one short night or several. The other is the circadian rhythm, the body’s 24 hour clock that lowers alertness at set times [3].
The AAA Foundation for Traffic Safety compared crash rates by sleep in the prior 24 hours, using federal crash data from 2005 to 2007 [4].
Comparison compiled by Safety Behind the Wheel Foundation
| Sleep in the past 24 hours | Crash rate compared with 7 or more hours |
|---|---|
| 6 to 7 hours | 1.3 times |
| 5 to 6 hours | 1.9 times |
| 4 to 5 hours | 4.3 times |
| Less than 4 hours | 11.5 times |
Hours awake add a second layer. The National Institute for Occupational Safety and Health (NIOSH) likens 17 hours awake to a blood alcohol concentration (BAC) of 0.05%. After 24 hours, the comparison is a BAC of 0.10% [3].
The body clock sets the danger hours: NIOSH training material reports that drowsy driving crashes and near misses peak from 4 to 6 a.m. Smaller peaks fall from midnight to 2 a.m. and from 2 to 4 p.m. [5]. If our technician woke at 7 a.m., the 3 a.m. drive home starts 20 hours later, past the 17 hour mark and in the early morning low (our calculation).
Night shifts, long shifts and the drive home
Shift timing and shift length each add risk. In research summarized by NIOSH, night shifts carried about 28% more risk of accidents and errors than day shifts. Likewise, 12 hour shifts carried about 28% more risk than 8 hour shifts. Shifts that were both long and overnight carried the most [5].
- Extended shifts: In a nationwide study published in 2005, 2,737 first year medical residents filed 17,003 monthly reports. After shifts of 24 hours or more, their odds of reporting a crash were 2.3 times higher, and of a near miss 5.9 times higher [6]. Each extended shift in a month raised their risk of a crash on the commute home by 16.2% [6].
- Night shifts: In a 2016 study, 16 night shift workers drove a test car on a closed track. Each made one 2 hour drive after normal sleep and one after a night shift. After the night shift, 6 of 16 drives had near crashes and 7 were stopped early for safety. The drives after normal sleep had none [7].
Overtime and back to back shifts: how fatigue stacks up
Fatigue also builds across a run of shifts when the rest gaps are too short for full sleep. NHTSA’s Countermeasures That Work cites a 2008 national survey on work hours. People working 50 or more hours a week were 3 times as likely to report drowsy driving each week as those working 30 to 40 hours [8].
In the resident study, months with 5 or more extended shifts brought 2.39 times the odds of falling asleep while driving. The odds of nodding off in stopped traffic were 3.69 times higher [6].
The checklist below adapts NIOSH’s shift schedule guidance, written for nurses but based on broader fatigue research, for any team that drives [5].
Hours of service rules: a benchmark with a gap
For truck drivers, the Federal Motor Carrier Safety Administration (FMCSA) sets hours of service limits. A property carrying driver may drive up to 11 hours after 10 hours off duty, but not past the 14th hour after coming on duty [9]. Other rules require a 30 minute break after 8 hours of driving. They also bar driving after 60 hours on duty in 7 days, or 70 in 8, until a 34 hour break resets the count [9].
These rules apply only to commercial motor vehicles. Examples include vehicles rated at 10,001 pounds or more and those carrying more than 8 people, including the driver, for pay [9]. Most employees in cars, minivans and light pickups fall outside them, so the employer’s schedule is the main fatigue control.
Rules alone do not guarantee rest. In 2014, a tractor trailer going 65 mph in a 45 mph work zone in New Jersey hit slowing traffic, killing 1 person [10]. The National Transportation Safety Board (NTSB) found the driver was fatigued. He had been awake about 28.5 hours, after an overnight drive of about 800 miles from home to start his shift [10].
The crash came 13 hours 32 minutes into a 14 hour duty day. The carrier had no written policy on fatigued driving or commuting distance. NTSB recommended a fatigue program that addresses commuting [10].
Time pressure: realistic appointments, routes and breaks
Fatigue and hurry feed each other, since a driver who falls behind skips breaks and a tired, late driver is tempted to speed. The Occupational Safety and Health Administration (OSHA) advises employers to make sure workloads and schedules let employees drive at safe speeds and follow hours of service rules [11].
- Book windows, not exact times. A 2 hour arrival window absorbs traffic, weather and rest stops.
- Plan at real speeds. Use typical traffic, and add time for parking, loading and paperwork.
- Put breaks in the ETA. NIOSH’s shift work guidance favors breaks every 2 hours over 4- to 6 hour gaps [5]. Use the same rhythm on long drives.
- Cap daily stops. If a route only works with speeding, drop a stop.
- Stop rewarding speed. Don’t rank drivers by jobs per day or penalize late arrivals caused by safety stops.
- Let the office carry the delay. Dispatch, not the driver, updates the customer, as our workplace distracted driving policy guide explains.
Trip planning rules: drive, split or defer
Clear rules take the guesswork out of decisions made while tired. These Drive With Care rules of thumb come from the risk thresholds above, so adapt them to your operation. For weather, routes and check ins, see our guide to journey management for employees.
Comparison compiled by Safety Behind the Wheel Foundation
| If this is true | Then do this |
|---|---|
| Less than 5 hours of sleep in the past 24 | No solo work driving that day. Reassign, ride along or defer. |
| The driver will have been awake 17 or more hours on arrival | Split the trip with an overnight stay, add a rested second driver or reschedule. |
| The drive falls between midnight and 6 a.m. | Move it to daylight. If you can’t, use a rested second driver or a planned rest stop. |
| A shift of 12 or more hours, or an overnight shift, just ended | Ride, nap room or hotel by default. A short nap before any drive. |
| The drive is longer than 2 hours | A stop of at least 15 minutes every 2 hours, built into the ETA. |
| Work time plus driving would top 14 hours | Book lodging and finish the next day. |
| The driver says they are too tired | Defer the trip with no penalty. The supervisor finds another option. |
Supervisors, self reports and the right to stop
Self reporting matters, but it is fragile. In a 2023 AAA Foundation simulator study of late night driving, 75% of drivers who rated their drowsiness as low were objectively moderately or highly drowsy [12]. More than 75% of those who felt extremely drowsy kept driving when they could have stopped [12]. A 2022 AAA Foundation review adds that admitting drowsiness at work often carries stigma [13].
So make speaking up easy, but don’t let schedules depend on it. NIOSH warns managers against pressuring workers into extra shifts, noting that tired workers have caused fatal vehicle crashes [5].
Give every employee who drives stop authority: the right to refuse or end a drive when unfit, and to defer the trip without losing pay or standing. Have HR and legal counsel review any policy that touches pay, discipline, privacy or labor agreements.
Building a fatigue risk management system
A fatigue risk management system (FRMS) manages fatigue like any other workplace hazard. NIOSH lists it first among employer steps and describes it as science based, data driven and built for continuous improvement [3, 5]. In plain terms, an FRMS ties five jobs together:
- Policy: written hour limits, rest rules and stop authority.
- Prevention: schedules, staffing and trip rules that keep fatigue low.
- Detection: fatigue reports, near miss reports and fatigue checklists [3].
- Health: sleep training for workers and managers, plus sleep disorder screening [3]. The American Academy of Sleep Medicine (AASM) advises employers with safety sensitive jobs to include screening for obstructive sleep apnea, which interrupts breathing during sleep [14].
- Learning: incident reviews and fixes that change the system.
For motor carriers, FMCSA worked with Transport Canada and Canadian provincial agencies to build the North American Fatigue Management Program, launched in July 2013 [15]. It covers company culture, education, sleep disorder screening and treatment, scheduling and fatigue monitoring technology [15].
NHTSA rates employer drowsy driving programs 2 out of 5 stars, meaning evaluation evidence is limited but programs may work if done well [8]. Track your own results. See our guide to building a workplace motor vehicle safety program.
Reviewing incidents for fatigue
Fatigue leaves no blood test, so it is found only when someone asks. NIOSH advises adding sleep history to incident investigations [3]. OSHA says every crash should be reported and reviewed for its root cause [11]. Include near misses and commute crashes after long shifts, which national work death counts leave out [2]. Ask privately, as fact finding rather than blame.
Then fix the system, whether that means the schedule, staffing, route or policy. Keep health questions, such as sleep disorders or medicines, in a confidential process.
Frequently asked questions
Can a drowsiness alert in the vehicle replace a fatigue policy?
No. NIOSH lists fatigue alert technology as one employer tool [3], but an alert sounds only after drowsiness has set in. Treat it as a backup to schedules, rest rules and stop authority.
Do hours of service rules apply to employees who drive company cars?
Usually not, because federal hours of service rules cover commercial motor vehicles, such as those rated at 10,001 pounds or more [9]. For most car and pickup drivers, the employer’s own policy sets the limits.
How many hours off should workers have between shifts?
NIOSH’s shift work guidance recommends at least 11 hours between shifts [5]. Keep long travel out of that gap. That way, the gap leaves room for the 7 or more hours of sleep that AASM recommends for adults [14].
Can an employee refuse to drive when too tired?
Strong fatigue policies give drivers stop authority and let them defer trips without penalty. Legal protection for a specific worker depends on the job, the law and any contract. Ask HR or a qualified attorney.
How often should employees take breaks on long drives?
Plan a stop of at least 15 minutes about every 2 hours, built into the schedule. NIOSH’s shift work research favors 2 hour break intervals over longer gaps [5]. If warning signs show up sooner, stop sooner.
The bottom line
Recommendation from Safety Behind the Wheel Foundation
Fatigue is a scheduling problem before it is a driving problem. Cap long and overnight shifts and protect at least 11 hours off. Make a ride or a bed the default after a long shift. Then give every driver the right to stop or defer a trip without penalty. Check every incident for sleep loss.
Related articles
- Drowsy driving: warning signs, hidden risks and what really works
- Workplace motor vehicle safety program: a step by step employer guide
- Journey management for work drivers: weather, breakdowns and check ins
- Work crash and near miss investigation: a step by step employer guide
- Distracted driving policy at work: a guide for employers and drivers
Sources and further reading
- 1U.S. Bureau of Labor Statistics (BLS). Census of Fatal Occupational Injuries Summary, 2024. USDL-26-0230. February 19, 2026. bls.gov/news.release/cfoi.nr0.htm
- 2BLS. Handbook of Methods: Census of Fatal Occupational Injuries, Concepts. Updated February 25, 2025. bls.gov/opub/hom/cfoi/concepts.htm
- 3National Institute for Occupational Safety and Health (NIOSH). Driver Fatigue on the Job. Last reviewed April 3, 2024. cdc.gov/niosh/motor-vehicle/driver-fatigue
- 4Tefft BC. Acute Sleep Deprivation and Risk of Motor Vehicle Crash Involvement. AAA Foundation for Traffic Safety. December 2016. aaafoundation.org/research/acute-sleep-deprivation…
- 5NIOSH. Training for Nurses on Shift Work and Long Work Hours: Module 3 (pages 12 to 13), Module 5 (pages 5 to 10, 15 and 17) and Module 11 (pages 2 and 5). Pages last reviewed March 31, 2020. Training home; Module 3, p. 12; Module 5, p. 5; Module 5, p. 6; Module 5, p. 17; Module 11, p. 2; Module 11, p. 5
- 6Barger LK, Cade BE, Ayas NT, et al. Extended work shifts and the risk of motor vehicle crashes among interns. New England Journal of Medicine. 2005;352(2):125-134. January 13, 2005. doi.org/10.1056/NEJMoa041401
- 7Lee ML, Howard ME, Horrey WJ, et al. High risk of near-crash driving events following night-shift work. Proceedings of the National Academy of Sciences. 2016;113(1):176-181. Published online December 22, 2015. doi.org/10.1073/pnas.1510383112
- 8National Highway Traffic Safety Administration (NHTSA). Countermeasures That Work: Drowsy Driving, Employer Programs. Accessed October 3, 2026. nhtsa.gov/book/countermeasures-that-work/…/employer-programs
- 9Electronic Code of Federal Regulations (eCFR). 49 CFR 395.3, Maximum driving time for property-carrying vehicles, and 49 CFR 390.5, Definitions (commercial motor vehicle). Up to date as of October 1, 2026. ecfr.gov … 395.3; ecfr.gov … 390.5
- 10National Transportation Safety Board (NTSB). Multivehicle Work Zone Crash on Interstate 95, Cranbury, New Jersey, June 7, 2014. Highway Accident Report NTSB/HAR-15/02. Adopted August 11, 2015. ntsb.gov (PDF)
- 11Occupational Safety and Health Administration (OSHA). Motor Vehicle Safety: Employers. Accessed October 3, 2026. osha.gov/motor-vehicle-safety/employers
- 12Gaspar JG, Carney C. Drowsiness and Decision Making During Long Drives: A Driving Simulation Study. AAA Foundation for Traffic Safety. March 2023. aaafoundation.org/research/drowsiness-and-decision-making…
- 13AAA Foundation for Traffic Safety. Countermeasures to Reduce Drowsy Driving: Results of a Literature Review and Discussions with Experts. September 2022. aaafoundation.org/research/countermeasures-to-reduce-drowsy-driving…
- 14American Academy of Sleep Medicine (AASM). Insufficient Sleep and Work Performance (health advisory). Adopted September 14, 2018. aasm.org/advocacy/position-statements/insufficient-sleep-work-performance-health-advisory
- 15Federal Motor Carrier Safety Administration (FMCSA). North American Fatigue Management Program. Last updated April 24, 2026. fmcsa.dot.gov/research-and-analysis/research/north-american-fatigue-management-program
This article reflects the safety priorities of fatigue research, occupational sleep medicine and fleet safety. It is general education, not legal, medical or professional advice for any individual or company. Workers should talk with a clinician about sleepiness or sleep disorders. Employers should have policies on hours, discipline, privacy and labor agreements reviewed by qualified HR and legal counsel. Rules, data and research change, so verify details with official sources. Reviewed October 2026.
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