Prevalence of daytime sleepiness in a population of drivers

The prevalence of excessive daytime sleepiness in the general population is generally quoted to be between 0.5 and 5%, but even wider ranges can be found, from 0.3 to 13%.1 This rather wide range is due to the variability in methodologies and populations used. Because “the sleepy driver” is a well-recognized public health hazard,2 we sought to estimate the prevalence of sleepiness at a department of motor vehicles. We administered the Epworth Sleepiness Scale (ESS) to 620 consecutive individuals 16 years or older who presented to the Department of Motor Vehicles in Madison, WI, for various reasons related to driving. The ESS is an 8-item questionnaire where each question is answered with a score from 0 (would never doze) to 3 (high chance of dozing), yielding a total between 0 (minimum) and 24 (maximum sleepiness). Questions inquire into the tendency to fall asleep during the following circumstances: 1) sitting and reading, 2) watching TV, 3) sitting inactive in a …