my only issue with it is the morning after issue. Last night i had half a bottle of wine, finishing the last glass at about 11pm. At what time was i ok to drive?
I'd be all for widely available, effective and cheap self testing kits to make sure that i never risked it.
The rule of thumb I've seen is that the average male metabolises about a unit an hour. 1 unit = 10ml of pure alcohol. A standard wine is, say, 12.5% alcohol. Half a standard bottle = 375ml. Thus - 3 hours to metabolise (if you drank all of it at the same time, which you won't have done, of course). Thus, if you finished at 11pm; you should be clear at 2am. Add on, say, 2 hours for safety = 4am. All, imo, like. I'm not qualified in this field!