Drowsy Driving Among Older Adults: A Literature Review

2 Disclaimer The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the information presented herein. This document is disseminated under the sponsorship of the Department of Transportation's University Transportation Centers Program, in the interest of information exchange. The U.S. Government assumes no liability for the contents or use thereof. The order of the last five authors is in alphabetical order. The goals of this literature review are to better understand the risk factors associated with drowsy driving, particularly those strongly affecting the older driver population, and to serve as the background information for the development of a questionnaire on this topic. The review is divided into two main sections: drowsy driving risk factors and countermeasures. Topics reviewed in the risk factors section include: sleep deprivation and disorders, medications that may cause drowsiness as a side effect, work schedules, circadian rhythm, personality attributes, alcohol use, lifestyle, and environmental characteristics. Topics reviewed in the countermeasures section included: common practices (e.g. turning up the volume of the radio), caffeine, napping, sleep disorder treatments, lifestyle, work schedules, alertness maintenance and in-vehicle technology. Emphasis was placed on finding studies performed on older drivers, although studies done on younger or middle-aged drivers were not excluded. Sleep disorders and various medical conditions and medications that may cause drowsiness are prevalent in the older population, putting older drivers at an increased risk of a drowsy driving crash. The circadian rhythm creates a risk for those driving between the hours of midnight and 6:00 AM and again in the mid-afternoon. Unusual work schedules, certain personality traits, alcohol use, and lifestyle practices (e.g. smoking) and monotonous road conditions may all lead to driver sleepiness and crash risk. Common practices to combat drowsy driving such as rolling down a window or turning up the radio's volume are not effective in combating drowsiness. Caffeine intake may help alleviate sleepiness, especially if combined with a short nap. Many non-medication treatments may benefit older adults suffering from sleep disorders or problems, but more research is needed to ascertain whether these treatments increase driving safety. Numerous types of in-vehicle drowsiness-detection technology have been developed to alert drivers before they crash. Overall, more research is needed to further understand drowsy driving risk factors and countermeasures regarding drivers age 65 and older. Findings indicated a strong need for more research on older drivers' crash risk …