Sleep and Driving: Guidelines

Tiredness can kill. That is the title of guidance issued by DVLA on the dangers of driving without enough sleep. Of course, most people will be aware of any side effects from medication and not to drive after consuming alcohol, but unfortunately some do not heed the risks.

Many more will be less aware of the need for adequate sleep and how it affects their alertness and Ability To Concentrate and react. Some may even ignore the signs believing they will be able to fight the signs of sleepiness and stay alert.

The Facts

  • Up to one fifth of road accidents may be attributed to drivers falling asleep
  • Driver ‘inattention’ is invariably due to drowsiness
  • In sleep related crashes, emergency braking is absent and they are less likely to respond to conditions
  • 18-30 year old males are more likely to fall asleep driving late at night
  • Long journeys at holiday times are more likely to cause fatigue
  • 40% of crashes involve people who are driving to work

Secondary contributing factors include, the body’s inclination to sleep after a large meal and changes in body rhythm related to the time of day. There is a natural tendency to feel sleepy during ‘siesta’ time – mid afternoon and during the early hours of the morning.

DVLA Suggests…

  • Taking breaks on long journeys
  • Being aware of and not ignoring the symptoms of fatigue
  • Stopping if you feel drowsy
  • Having a cup of coffee and then a short nap

Short term measures such as opening the vehicle’s window or turning up the radio should only be used until a safe space can be found to stop.


In sleep-related crashes, all drivers who fall asleep at the wheel have a degree of warning. There is no excuse for falling asleep at the wheel and it is not an excuse in law.

There are a number of medical conditions that cause excessive sleepiness. These may make driving unsafe. These include:

  • Obstructive Sleep Apnoea
  • Obstructive Sleep Apnoea (OSA)
  • Illnesses of the nervous system, such as Parkinson’s
  • Disease, MS, and MND
  • Narcolepsy

Medical conditions causing sleepiness must be reported to the DVLA who will send you a questionnaire asking for details about the your condition. This also asks for your consent for the DVLA Medical Advisers to ask for information from your GP.

When the medical investigation is complete a decision is made about the driving licence and, in some instances when a licence is issued, it will be subject to more frequent renewals (these are free of charge).

Safe driving depends on being alert and in control. Passengers and drivers should be aware of any signs that suggest that the driver is feeling drowsy. On long journeys, if possible, alternate drivers with each driving for a maximum of two hours. Plan journeys in advance and make sure that you have extra sleep the previous nights and try to avoid the danger hours after lunch and between midnight and 6am. Keep alert, keep safe!