Back in 1992, the World Medical Association [WMA] recommended that no country in the world should permit drivers to have a blood-alcohol concentration [BAC] higher than 0.05 percent, on the basis that medical research had proved anything above this level created an unacceptable level of risk.

At that time, scores of countries had a limit of 0.08 BAC [Source: Drive and Stay Alive], although many American states still permitted levels up to almost double that.
Some countries started to take notice of the new medical research advice but in 2007 the WMA felt it necessary to repeat the 0.05% recommendation.
Now, among the ~30 most developed nations in the world, arguably only two have failed to cut their BAC limit to 0.05%, namely the southern part of the UK (meaning England and Wales) and so far every state in the USA except for Utah. (Way to go, Utah!)
Canada is sort of halfway there, with modest punishments for anyone caught between 0.05 and 0.08 percent, and higher punishments for those above 0.08%.
Which are the best countries in this context (leaving aside those nations which have an absolute ban on alcohol for religious reasons)? The answer is Norway, Sweden, and I believe Finland, too. In those places, the limit is just 0.02%, and even that exists only to allow for the small amounts of alcohol that are found in some medications and items such as mouthwash. And the penalties for being over 0.02% are very high, too.
And now, here in the USA, there is at last a significant push for a 0.05% BAC limit, by five immensely well-known names in the field of road safety:
- Former Secretary of Transportation, the Hon. Norman Mineta
- Dr Bella Dinh Zarr (NTSB)
- Dr. David Sleet (prev. CDC)
- Thomas Louizou (prev. USDOT)
- Marilena Amoni (prev. NHTSA)
Their organization is 05 Saves Lives