• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of injprevInjury PreventionVisit this articleVisit this journalSubmit a manuscriptReceive email alertsContact usBMJ
Inj Prev. Sep 2001; 7(3): 194–199.
PMCID: PMC1730738

Drowsiness, counter-measures to drowsiness, and the risk of a motor vehicle crash


Objectives—Knowledge of how different indicators of drowsiness affect crash risk might be useful to drivers. This study sought to estimate how drowsiness related factors, and factors that might counteract drowsiness, are related to the risk of a crash.

Methods—Drivers on major highways in a rural Washington county were studied using a matched case-control design. Control (n=199) drivers were matched to drivers in crashes (n=200) on driving location, travel direction, hour, and day of the week.

Results—Crash risk was greater among drivers who felt they were falling asleep (adjusted relative risk (aRR) 14.2, 95% confidence interval (CI) 1.4 to 147) and those who drove longer distances (aRR 2.2 for each additional 100 miles, 95% CI 1.4 to 3.3). Risk was also greater among drivers who had slept nine or fewer hours in the previous 48 hours, compared with those who had slept 12 hours. Crash risk was less for drivers who used a highway rest stop (aRR 0.5, 95% CI 0.3 to 1.0), drank coffee within the last two hours (aRR 0.5, 95% CI 0.3 to 0.9), or played a radio while driving (aRR 0.6, 95% CI .4 to 1.0).

Conclusion—Drivers may be able to decrease their risk of crashing if they: (1) stop driving if they feel they are falling asleep; (2) use highway rest stops; (3) drink coffee; (4) turn on a radio; (5) get at least nine hours sleep in the 48 hours before a trip; and (6) avoid driving long distances by sharing the driving or interrupting the trip.

Full Text

The Full Text of this article is available as a PDF (148K).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • McCartt AT, Ribner SA, Pack AI, Hammer MC. The scope and nature of the drowsy driving problem in New York State. Accid Anal Prev. 1996 Jul;28(4):511–517. [PubMed]
  • Pack AI, Pack AM, Rodgman E, Cucchiara A, Dinges DF, Schwab CW. Characteristics of crashes attributed to the driver having fallen asleep. Accid Anal Prev. 1995 Dec;27(6):769–775. [PubMed]
  • Lyznicki JM, Doege TC, Davis RM, Williams MA. Sleepiness, driving, and motor vehicle crashes. Council on Scientific Affairs, American Medical Association. JAMA. 1998 Jun 17;279(23):1908–1913. [PubMed]
  • Sagberg F. Road accidents caused by drivers falling asleep. Accid Anal Prev. 1999 Nov;31(6):639–649. [PubMed]
  • Horne JA, Reyner LA. Sleep related vehicle accidents. BMJ. 1995 Mar 4;310(6979):565–567. [PMC free article] [PubMed]
  • Johns MW. A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep. 1991 Dec;14(6):540–545. [PubMed]
  • Johns MW. Daytime sleepiness, snoring, and obstructive sleep apnea. The Epworth Sleepiness Scale. Chest. 1993 Jan;103(1):30–36. [PubMed]
  • Mickey RM, Greenland S. The impact of confounder selection criteria on effect estimation. Am J Epidemiol. 1989 Jan;129(1):125–137. [PubMed]
  • Greenland S. Dose-response and trend analysis in epidemiology: alternatives to categorical analysis. Epidemiology. 1995 Jul;6(4):356–365. [PubMed]
  • Reyner LA, Horne JA. Falling asleep whilst driving: are drivers aware of prior sleepiness? Int J Legal Med. 1998;111(3):120–123. [PubMed]
  • Reyner LA, Horne JA. Evaluation "in-car" countermeasures to sleepiness: cold air and radio. Sleep. 1998;21(1):46–50. [PubMed]
  • Horne JA, Reyner LA. Counteracting driver sleepiness: effects of napping, caffeine, and placebo. Psychophysiology. 1996 May;33(3):306–309. [PubMed]
  • Terán-Santos J, Jiménez-Gómez A, Cordero-Guevara J. The association between sleep apnea and the risk of traffic accidents. Cooperative Group Burgos-Santander. N Engl J Med. 1999 Mar 18;340(11):847–851. [PubMed]

Articles from Injury Prevention are provided here courtesy of BMJ Group


Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


  • MedGen
    Related information in MedGen
  • PubMed
    PubMed citations for these articles

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...