It Does Not Address the Real Problem
Over half the people currently convicted of drink-driving have a BAC over twice the 80mg limit. They are responsible for the overwhelming majority of drink-related fatalities, around 60% of which relate to the death of the drinking driver himself. These are people who are, for whatever reason, prepared to gamble not only with their driving licences, but with their lives. If they are quite willing to risk breaking the 80mg limit, or couldn't care less about it, then what difference can 50mg conceivably make to them? The real challenge for the authorities should be how to identify, detect and dissuade the small group of drivers who pose by far the highest risk.
It Would Encourage the Hard Core
The existence of a hard-core of otherwise law-abiding people, often middle-aged professional men, who drive when well over the limit in a knowing, calculated way has been much exaggerated. Most people who are caught when they should have had a good idea they were well outside the law are either outright villains, irresponsible thickheads, or chronic alcoholics. But this hard-core does exist, and they will have gained a considerable amount of comfort from the debate on the subject which has exposed the issue to be one of shades of grey rather than clear black and white, and from the publication of statistics which show that the dramatic increase in accident risks does not occur until some way over 80mg. They generally won't be driving over 160mg, and they may even feel that the debate has given some kind of moral justification for their behaviour. And many others, who broadly supported 80mg, but feel that 50mg is unreasonable, would be placed, in spirit at least, in the same camp as this hard-core.
It Would Lead to Unjust and Pointless Convictions
Even with the 80mg limit, every year thousands of people are convicted and banned when they had been drinking the night before and did not realise that they might still be over the limit. Many of these may sincerely believe that they never drink and drive at all. A 50mg limit would bring the threshold for this down from a heavy session to what, to many people, is a normal night in the pub. It would be distinctly possible that five pints of mild or ordinary bitter would leave you still over the limit the morning after. If you were drinking stronger beers, or had the odd glass of wine or spirits as well, or drank much after 11 pm, the risk would be that much greater. The government does nothing to publicise this, maybe because it would show up how flawed a law is when you may have no idea that you are breaking it.
It is also doubtful how much risk the morning-after driver really poses on the road. There is ample evidence that the degree of impairment of someone whose alcohol level is falling is much less than that of someone with the same, but rising, alcohol level. The effects wear off well before the alcohol is removed from the bloodstream. This is a recognised medical phenomenon known as the Mellanby Effect. The law fails to take this into account and offers no opportunity for mitigation if an alcohol level arises from drinking many hours before. This is unjust with the limit at 80mg, and would be doubly so if it was reduced to 50mg.
It Would Force Non Drink Drivers to Think Twice About Drinking At All
Given that, with a 50 mg limit, it would be so easy to unwittingly fall foul of the law, many responsible people who depend on a driving licence for a living, from sales reps to bus drivers, would start to wonder when they could ever safely have an alcoholic drink. They would feel constrained to have no more than a single bottle of beer or glass of wine in the evening if they were driving the next day, and only really be able to relax in the first few days of a long holiday.
Over three quarters of adults hold a driving licence, and those who don't are disproportionately female pensioners. Probably over 50% of adults drive on any given day. Outside London, 80% of journeys to work are made by car. A large majority of the working population would have to think carefully about their drinking patterns in a way they never had to before, even if they never touched so much as a half of shandy immediately before driving. It's difficult to escape the conclusion that a 50 mg limit would bring us closer to a kind of back-door Prohibition.
It Would Close Thousands of Pubs
Contrary to much half-baked comment, a 50mg limit would not lead to the rapid closure of many high-profile country pubs. They are already increasingly concentrating on food rather than appealing to drinkers, and this trend would intensify. Few out-of-town pubs would be able to survive without a heavy emphasis on food, whether of the cheap'n'cheerful family pub variety, or the upmarket "country dining pub".
The pubs that would suffer are the smaller, more traditional ones which retain a higher proportion of wet sales and are unable to offer extensive family facilities or elaborate à la carte menus. These are not just isolated rural pubs - they are pubs in villages, in the suburbs, on the urban fringe and in small towns, in fact anywhere outside inner urban areas and the centres of big towns and cities.
If you watch pub customers who arrive by car, in most cases the driver will have at least one alcoholic drink, although very rarely in my observation enough to say with any certainty that they will be over the 80mg limit. If the law was changed, some drivers would still visit pubs but drink less or nothing, others would not bother going to the pub at all, a few would carry on regardless and break the law. But the overall impact on trade all points one way, and that is downwards.
Many pubs are already struggling, particularly the kind I have mentioned, and even a 5 or 10% decline in trade would push a fair few over the edge. If the 50mg limit was brought in, I would not be surprised if, over ten years, at least ten thousand pubs closed which would have stood a good chance of remaining open if 80mg had still been in operation. These would include many of the best-loved and most traditional pubs. That is a terrible price to pay for something where the potential benefits are so marginal and unproven, and, in the view of many, non-existent. And, as more pubs closed, the hard core drink-drivers would travel further, thus increasing the risk on the roads.
It Would Discriminate Against the Countryside
The Labour government in power since 1997 has managed to raise the hackles of country dwellers on a wide range of issues including handguns, fox hunting, beef on the bone, fuel duties, the "right to roam" and the closure of rural post offices. Reducing the drink-drive limit would be another one to add to the list.
Compared with towns, in rural areas public transport is scarce or non-existent, the distances travelled to social gatherings are much greater, and the consequences of a driving ban are far more serious. What may be no more than a minor inconvenience in urban areas would be a major curb on the lives of country people. It has been described as "the gloom of the Scandinavian nanny state descending on the countryside".
To impose a 50mg limit would show a profound ignorance of the realities of rural life, and contempt for the concerns of people who live in the countryside.
It Would Bring the Law into Disrepute
It is well-nigh impossible to find any responsible individual or organisation prepared to argue publicly that the 80mg limit is too low, although some may have raised legitimate concerns about the level of penalties or the method of enforcement. However, a wide range of authoritative voices have spoken out against the reduction to 50 mg, including motoring organisations, several chief police officers, the Brewers and Licensed Retailers Association and most of the national newspapers, as well as thousands of individuals. Few of them are going to change their views overnight and decide they were wrong all the time - and certainly no law-abiding motorist forced to change their behaviour would feel at all happy about it.
Opinions would continue to be expressed that the 50 mg limit is unjustified, and that those who fell foul of it had been badly treated. There would be a two-tier attitude to drink-driving, where anyone convicted with a BAC over 80 mg was seen as deserving what is coming to him, but those with levels between 50 and 80 were widely considered unfortunate and unlucky. This would be particularly so if - as has been suggested - 50-80 offenders received a fine and penalty points, but were not disqualified from driving, even though obviously that option in other respects would be the lesser of two evils. The end result would not advance the cause of road safety, or the standing of the police in public opinion.