Yes, it's seeing if you can resist the temptation to have any alcohol at all. Tough, but cheap.
I've posted before about Matthew Walker's book, Why we sleep. It's a must read for many professions. One of the most thought provoking statements was, Intoxicated, and you take more time to take action. (whatever that may be!) but tired, and during a micro-sleep, you make no decision at all.
Tiredness in the US causes more road traffic accidents than alcohol and 'substances' combined. He goes on to Controlled Release sleeping tablets, with horrifying statistics.