The first drink driving alcohol limits were made up because the "experts" didnt know what was a safe amount and what wasnt... https://www.theregister.com/2007/

The first drink driving alcohol limits were made up because the "experts" didnt know what was a safe amount and what wasnt... https://www.theregister.com/2007/10/22/drinking_made_it_all_up/ https://www.theregister.com/2007/10/22/drinking_made_it_all_... Today we know some people have gut bacteria that make alcohol from sugar so will fail an alcohol breath test if stopped by the police. Other factors include health of the liver and kidneys and other dietary factors, so in practice, its still all made up in my opinion.