In the United Kingdom, United States, Canada, South Africa, and Sri Lanka the legal blood alcohol limit is 0.08 mg per 100 ml.
This is too high as there is clear evidence that driving skills deteriorate and the risk of becoming involved in a crash increases from a blood alcohol concentration of 0.02 mg per 100 ml, says the author.
Because the legal blood alcohol concentration in most countries is so high, people often mistakenly believe that they may drive up to this limit, overlooking the fact that driving is impaired at lower concentrations, he adds.
To set a blood alcohol limit so high may adversely influence people's estimates of their relative risk of injury or death while driving. Drinking and driving policies and decisions about enforcement need to be hinged on the scientific evidence, he concludes.