My last post referred to the imminent reduction of the drink-drive limit in Scotland. On a non-beer-related forum I frequent, this led to a remarkable outbreak of paranoia, with ludicrous speculation about the Scottish police carrying out “hot pursuit” of suspected offenders across the border, and people wondering when they would ever be safe to have a drink, and asking whether they needed to buy a personal breathalyser if they sometimes enjoyed a few midweek pints and drove to work the following morning.
While I yield to no-one in my opposition to this law, in fact there are well-established rules of thumb that should help to set their minds at rest, but don’t tend to have the currency they once enjoyed. When I learned to drive in the 1970s, it was drummed in to me by my father and other adults that, to avoid falling foul of the law, I should drink no more than two pints of ordinary-strength beer when driving. Of course, in those days there wasn’t much else around other than ordinary-strength beer. And two pints was a figure that would keep you comfortably below the limit, not end up nudging against it.
This is borne out by this 1986 leaflet produced by the Transport and Road Research Laboratory which states clearly that if an 11-stone man drinks two pints of ordinary-strength beer, his blood-alcohol level would reach a maximum of 60 mg. Given this, it follows that drinking just one pint should not take you anywhere near a 50mg limit, and one and a half may well be OK for gentlemen of more substantial build. Of course nowadays the picture is clouded by the availability of many stronger beers, but if you’ve lost count of how much you’ve had it’s probably fair to say you’re not fit to drive the following morning. Whether you would think it worthwhile to go to the pub just to drink one pint is another matter.
The other point is that, regardless of how much you’ve had in the first place, alcohol is cleared from the system at the rate of about one unit an hour. This explains why people who’ve had a skinful can still be over the limit the following tea-time but, on the other hand, if you’ve had four pints and stopped drinking at 11 pm, you’ll probably have a blood-alcohol level of zero by 8 am the following morning, and are vanishingly unlikely to still be over the limit. It’s also important to remember that, while various factors such as the type of drink and whether or not you’ve eaten at the same time will affect how swiftly alcohol is absorbed into the bloodstream, the maximum potential blood alcohol level that any particular drink will produce remains unchanged. There’s no way that a half of lager, even if drunk on an empty stomach, is going to take you anywhere near.
But this reaction underlines the point that the key motivation behind this legislation is to make normal, responsible people think twice about drinking alcohol, not just immediately before driving, but most of the time. If the real objective was improving road safety, then an honest publicity campaign about how to keep within the law, including a much greater focus on the morning after, combined with an increase in targeted enforcement activity, would be much more effective. Knowing someone who has been breathalysed, even if they passed, is the best deterrent. But reducing the limit without any increase in enforcement will do nothing to deter those who are already breaking the current limit, and indeed may be perceived as legitimising their behaviour.
At the end of the day, it’s not about safety, it’s about denormalisation, and it certainly seems to be working.