Over-enthusiasm for stamping out drink-driving attracts attention away from road safety. Every day you see drivers on their mobile phones, confident that no-one, apart from the police, will object.
Yet they are four times more likely to crash, and that puts them at about the equivalent of 100mg of alcohol per 100ml of blood, which is 20 pints above the present drink-drive limit of 8mg.
This dangerous and casual attitude is a result of the mindset that says drink drivers cause most crashes and deaths. That was true 30 years ago, when 1,640 deaths occured in one year in Great Britain.
That figure has reduced steadily, by 46 fewer deaths per year on average to 280 in 2010.
Inflating the prevalence of drink-driving has given the hard-drinking hard core an impression that there is still safety in numbers.
If the Scottish Government does lower the drink-drive limit to come into line with Europe, it should also come into line with the penalties. Drivers caught between 50 and 80 are fined about £100 in France and Greece, reflecting the lower risk; there is no long-term disqualification.
Intriguingly, in Belgium, a driver is given a driving ban of three hours – long enough to allow his blood-alcohol reading to fall to a safer level.
MSP Mark McDonald (your report, 3 November) seems to think that being slightly over the limit is equivalent to being significantly over the limit.
Does he have a similar view when it comes to speed limits?
Does he think that driving at 35mph is comparable to 65 in a 30 zone? A court would fine the former but might disqualify the latter driver.
What is little understood by drivers is that there is an exponential increase in stopping distance as speed increases.
Similarly with drink, a small drink will not alter the relative crash risk factor (RCF) much beyond 1.00, but a small drink after consuming a large amount of alcohol raises the risk exponentially, most dramatically at about double the drink drive limit.
At just under 160mg the RCF is 10.44, itself an alarmingly high figure, yet at over 160 the RCR rises to an even more terrifying 21.38.
Given the fall of drink driving and the rise of other driving menaces, it is time to turn from sentiment to science.