This could be a one off mistake but more likely a regular pattern of behaviour that the perpetrator was unaware that he was committing

http://mobile.abc.net.au/news/2018-10-08/james-schnelle-colonel-us-marines-drink-driving-stood-down/...

A lot of people don't realise just how few drinks make you over . 05 but to be mid range this guy has no idea what it takes.
U.S. sobriety tests often do not involve actual measuring instruments as here