Author: Sasha Tanner
Driving under the influence of alcohol and other drugs is dangerous and illegal, but how much time should pass before it is safe to get behind the wheel? After a night of drinking, symptoms can persist well into the morning, depending on alcohol intake, tolerance levels, body composition, and other factors. Though the lines are blurred, a team of experts from Australia caution that hangovers are just as impairing to the driving task as driving immediately after a drink.
Gathering Information on Impaired Driving and Hangovers
This study was conducted in the Australian Capital Territory (ACT) with the following objectives in mind:
- Calculate the instances of impaired driving and hungover-related driving in the population.
- Understand public perceptions towards hungover-related driving.
- Outline public health policy recommendations to reduce instances of hangover-related driving.
Furthermore, the researchers developed a survey and distributed it to randomly selected ACT residents who were 21 years or older, had a valid driver’s license, and drank alcohol at some point.
Survey Characteristics
A total of 761 participants completed a 10-minute survey that inquired about basic demographic information, alcohol use, and driving behaviors. Participant characteristics included, but not limited to, the following information:
- 57% were male and 43% were female
- About half were in the age group of 30-39 years old
- 84% had a full license
- 48 participants (10%) had a Probationary P1 license
- 34 participants (7%) had a Probationary P2 license
- 2% had a suspended license
- Approximately 3 out of 4 participants drive every day of the week
Analyzing the Data: What to Know
Based on the participants’ answers, the researchers found that:
- 38% drove with a hangover at least once in their lives
- 62% reported a change in driving capabilities, while 39% did not see a difference
- 65% believed that reaction time slows down while hungover
- 74% showed willingness to test for ability to drive while hungover
- 60% believed that driving with a hangover poses a risk to public safety, and
- 59% report that enforcement discourages hangover impaired driving.
Employment status and education level showed no strong association with alcohol impaired driving. However, age and sex mattered. Here is what the data shows:
- Sex and Alcohol Impaired Driving Stats: 25% of men reported alcohol impaired driving versus 31% of women.
- More Older People Reported Alcohol Impaired Driving: 24% of people aged 30-49 years versus 40% aged 50 or above.
- Seasoned Versus Novice Drivers: While younger people were ~2.5 times more likely to drive while impaired compared to older generations, both reported engaging in hangover impaired driving.
Policy Implications
There is a gap in policies that address hangover impaired driving since people assume that they can drive effectively in the morning. Yet, other symptoms of intoxication persist, such as reduced attention, coordination, and cognitive function with a slowed reaction time despite little to no alcohol concentration in the blood.
Here are some potential recommendations from the study:
- Objectivity and Subjectivity: More research must investigate objective measures of hangover impaired driving, including cognitive performance tests. Subjective responses only account for individual perceptions of hangover symptoms, law enforcement, time since last drink, etc.
- People of Focus: Education and preventative measures should be targeted towards younger and probationary drivers since they are more likely to engage in alcohol or hangover impaired driving.
- Effective Messaging: Campaigns should design public messaging to advocate against driving while hungover.
- Ex. “Zero BAC does not mean zero impairment” or “The morning after can be just as dangerous as the night before”.
Traffic safety starts with making smart decisions. Feeling “off” after a night of drinking will affect driving abilities. For more information on hangover impaired driving, check out the study below!
Source: Aitken, B., E. Ayre, L.D. Downey, & A. Hayley. (2025). Hungover in the ACT: A survey on public attitudes and behaviours related to driving with an alcohol hangover (Report No. RSG2023013). ACT Government; Swinburne University of Technology. https://www.cityservices.act.gov.au/__data/assets/pdf_file/0011/2843768/Report-Swinburne-Uni-Hungov…
