Review of effectiveness of laws limiting blood alcohol concentration levels to reduce alcohol-related road injuries and deaths

It aimed to assess how effective the blood alcohol concentration (BAC) laws are at reducing road traffic injuries and deaths. It also assessed the potential impact of lowering the BAC limit from 0.081 to 0.05. The review concluded that there is strong evidence that someone’s ability to drive is affected if they have any alcohol in their blood.

The review aimed to assess how effective the blood alcohol concentration (BAC) laws are at reducing road traffic injuries and deaths. It also assessed the potential impact of lowering the BAC limit from 0.081 to 0.05.

The review examined:
• Drink-driving patterns and the associated risk of being injured or killed in a road traffic accident
• How BAC limits and related legislative measures have changed drink-driving behaviour and helped reduce alcohol-related road traffic injuries and deaths
• Models estimating the potential impact of lowering the BAC limit from 0.08 to 0.05 in England and Wales
• Lessons from other countries on using BAC laws as part of overall alcohol control and road safety policies.

A conceptual framework was used to show how, in theory, a law limiting drivers’ BAC levels could lead to changes in how much drivers drink and the number of alcohol-related road traffic injuries and deaths. The review of evidence tested these theoretical links and the robustness of the underlying assumptions.

The review concluded that:
• There is strong evidence that someone’s ability to drive is affected if they have any alcohol in their blood. Drivers with a BAC of between 0.02 and 0.05 have at least a three times greater risk of dying in a vehicle crash. This risk increases to at least six times with a BAC between 0.05 and 0.08, and to 11 times with a BAC between 0.08 and 0.10.
• Studies consistently demonstrate that the risk of having an accident increases exponentially as more alcohol is consumed.
• Younger drivers are particularly at risk of crashing whenever they have consumed alcohol – whatever their BAC level – because they are less experienced drivers, are immature and have a lower tolerance to the effects of alcohol than older people.
• Overall, there is sufficiently strong evidence to indicate that lowering the legal BAC limit for drivers does help reduce road traffic injuries and deaths in certain contexts.