An evaluation of the effects of lowering blood alcohol concentration limits for drivers on the rates of road traffic accidents and alcohol consumption: a natural experiment

Study found that lowering the driving blood alcohol concentration limit to 0.05g/dL from 0.08 g/dL in Scotland was not associated with a reduction in road traffic accidents but was associated with a small reduction in alcohol consumption measured by per-capita on-trade sales.

The researchers suggest that one plausible explanation is that the legislative change was not suitably enforced, but they acknowledge that changing the legal blood alcohol concentration (BAC) limit for drivers in isolation does not improve road traffic accident (RTA) outcomes.

 

A commentary notes that the best evidence indicates that new BAC laws prevent RTAs when they are effectively enforced (i.e. resources are required to conduct highly visible enforcement activities) and are supported by public communication campaigns. Other legal initiatives (e.g. random breath testing) and public education initiatives generally enhance the safety effects of BAC laws.