I am amused by andy hughes:
"Since alcohol impairment depends on a load of variables -age, weight, stress levels, recent food intake, and so on, surely it would be better to simply ban for life anyone who drinks and drives. "
right so for DD you go with the 1 strike and out but for almost every other crime it's 100+ strikes and still not out, don't BS I've read your threads on burglary!
Anyway, back to DD, we should lower the DD limit to trace only, then there is no ambiguity, then apply the law as it is.
I know a guy who drinks 4-5 pints of stella every day and drives home, been breathalysed many times and passed, tell you why? because the limit is ridiculously high, you have to be rat ar5ed to fail and to fail the next day is almost impossible. What most people forget is that it's 1 unit per hour dissipatuion + the last one doesn't register for 20 minutes. QED drink 5 pints in 3 hours you've actually had 2.5, passable.