MrFlibble:
“Driving behaviour is impaired more during a phone conversation than by having a blood alcohol level at the UK legal limit.”Source: Transport Research Laboratory, Report Reference Number TRL547.
I’d go along with that. Whilst the drink would impair your judgement, it would not distract your attention; in fact the knowledge that you have drunk excess alcohol might well make you concentrate harder, although that would of course be cancelled out by the effects of the alcohol on your co-ordination and reactions.
I confess to having had a couple of lapses of attention even with a hands-free, and I’m sure I’m not alone.