The consumption of alcohol, even in relatively small amounts, increases the risk of being involved in a crash for motorists and pedestrians. Not only does alcohol impair processes critical to safe road use, such as vision and reaction time, it is also associated with impaired judgement and so is often linked to other high-risk road use behaviours such as speeding or not using seat-belts. In many countries, research indicates that considerable proportions of drivers, motorcyclists and pedestrians have alcohol in their blood in sufficient concentrations to impair their road use skills.

While the profile of drink-drivers differs somewhat between regions, there are a number of factors that increase the risk of crashes involving drinking and driving. For example, young male drivers are at a high risk of such crashes, and crashes involving alcohol are more frequent at night.