The drink drive limit varies between countries and states. In the United States, the legal limit is 0.08% blood alcohol content (BAC), which means that if your BAC is above this level, you are presumed intoxicated in every state. However, many states also have other limits in place as well, such as a "zero tolerance" level that applies to certain drivers, such as teenage drivers who arent supposed to be consuming alcohol anyway, or commercial drivers such as bus and truck drivers. In the UK, the legal limit is 0.08% BAC in England, Wales, and Northern Ireland, and 0.05% BAC in Scotland. In Hong Kong, the legal limit is 0.05% or BrAC 0.22 mg/L or urine 0.067% . Its important to note that impairment begins with the first drink, and the only safe driving limit is 0.00% . Therefore, its best to err on the side of caution and avoid drinking and driving at all.