Sleep-related vehicle accidents: some guides for road safety policies

Sleep-related vehicle accidents (SRVAs) are a common form of highway accident, often wrongly attributed to other causes. SRVAs typically involve running off the road or into the back of another vehicle, with no braking beforehand. Because of a high impact speed these accidents are often serious. SRVAs peak around 02:00–06:00 h and 14:00–16:00 h, when daily sleepiness is naturally higher. Hence, time of day is a critical factor, as important as the duration of the drive. Most SRVAs are not due to sleep pathology. Many are work-related. Non-sleeping “rest” is no substitute for sleep. Sleep does not occur spontaneously without warning, and is preceded by feelings of increasing sleepiness of which drivers are quite aware. Driving impairment is usually worse than is realised by the sleepy driver. The best countermeasure is sleep, or even a short nap. Even more effective is the combination of a nap with caffeine.