While some passing references are made, there is no serious attempt made to analyse types of drink-drivers, whether law-abiding or currently illegal, what their motivations are and how they might respond to a change in the law. There is little point in advocating a change in the law unless you provide some analysis of the likely level of compliance.
There is an assumption that cutting the legal limit will reduce the numbers driving when well over the limit, which is questionable in itself and indeed somewhat unreasonable anyway. This is similar to the oft-heard claim that increasing the average price of alcoholic drinks will reduce the number of “problem drinkers”. Well, it might, but it will hurt responsible drinkers too, and the problem drinkers are probably the least likely to be swayed by price increases. If the aim is to cut the number of over-80mg drivers, then surely the best way of doing it is to devote more resources to testing, rather than penalise those at lower alcohol levels in the vague hope it will also influence those currently breaking the law.
The claimed reductions in fatalities are at the same time dubiously specific, but cover a very broad range. Given some of the holes in the research it's difficult to attach much confidence to them. 43 to 168 is one hell of a range! Could it not easily be 0 to 125? Or -43 to 82? I tend to believe that if this was implemented any reduction in casualties would be so small as to be lost in the noise of wider trends. After all, road fatalities in Great Britain fell by 12% between 2008 and 2009 without any significant changes in traffic legislation.
Mandatory one-year bans at 50mg, as proposed by North, would give us the strictest legal regime of any country in Europe with a 50mg limit. All countries with a 50mg limit either do not impose bans until some way above that level, or only impose short bans for lower level offenders.
The report does not recommend the general adoption of “unfettered discretion” (often incorrectly described as "random testing"), but it does say that it should be allowed in defined circumstances where there was a high risk of offences being committed, such as on the roads surrounding major sporting events. However, the worry with that is that the power could easily be abused to harass specific individuals or establishments, who would have no legal comeback. It also acknowledges that senior police officers have stated that in their view their current powers do not in practice restrict them from carrying out breath testing. The prime restriction on testing is resources, not limited powers.
While it is presented as a road safety measure, there does seem to be an unspoken anti-drink agenda behind all of this. Lowering the limit would force responsible people who hold driving licences to consider their alcohol consumption more carefully, both immediately before driving and on the night before driving, and would also lower the bar as to what, in both circumstances, was considered acceptable. It is likely to prove a far more effective means of closing pubs than of saving lives on the road, just as the smoking ban has been far better at closing pubs than reducing smoking.
There is a very good official response to the report from the Association of British Drivers here – I can’t find much to disagree with in that.