Abstract

Many prescription and over-the-counter medications have potential effects that adversely impact driving, including dizziness, sleepiness, fainting, blurred vision, slowed movement, and problems with attention. Drivers may take one or more potentially driver impairing medications but may not be aware of the possible impacts on driving. This study utilized data from a survey of driving behavior in the United States in 2021 to quantify the prevalence of recent use of potentially driver impairing medication and driving after use, and to assess the association of healthcare provider warnings regarding medication effects with drivers’ likelihood of driving shortly after use.

Methodology

The current study investigated the prevalence of recent use of potentially driver impairing (PDI) medications in a representative sample of U.S. drivers. Data were from the Traffic Safety Culture Index, a national online survey of driver behavior carried out annually. In 2021, a set of questions was included on the use of six classes of prescription and over-the-counter medications, which were selected on the basis of their potential to impair driving and their having been detected in drivers in other recent studies. For each PDI medication that a respondent reported using, they were asked whether they had driven within two hours of using it. Respondents were also asked whether the medication was prescribed to them, and if so, whether a health care provider (e.g., a doctor, nurse, or pharmacist) had spoken with them about the possible side effects of the medication and its likely impacts on driving. (Response options for all questions were yes, no, and I don’t remember.)

The survey was administered in English and Spanish from July to August 2021 and the study was based on the responses of 2,657 respondents ages 16 and older who reported they possessed a valid driver’s license and had driven in the 30 days before they completed the questionnaire. Data were weighted to project results from the survey sample to the population of all U.S. drivers. All analyses were conducted using weighted data.

Results

• Approximately half of the drivers reported using one or more of the PDI medications examined in the past 30 days, while nearly one in five reported using two or more medications. Antihistamines and/or cough medicines were the most commonly used type of medication, reportedly taken by one third of drivers.
• Nearly half of drivers who reported using one or more PDI medications reported driving within two hours of using at least one medication, with higher proportions among those taking two or more medications (63.3%) or three or more medications (70.8%).
• Among drivers who took a PDI medication that was prescribed to them, the proportion that recalled receiving a warning from a healthcare provider about possible side effects and potential impacts on driving was lowest for antihistamines and/or cough medicines and highest for sleep aids, barbiturates, or benzodiazepines.
• Drivers who received a warning about a medication were 18% less likely to report having driven within two hours of taking that medication.