Once again, a summer drink-drive crackdown by police has found fewer people breaking the law.

This mirrors a similar reduction last Christmas and summer 2013.

Significantly fewer drivers were charged with drink-driving this year compared to the same two-week period last year. That is certainly good news. But does this mean a tougher Police Scotland attitude has been a success? There are two caveats.

First, are we comparing like with like? Last year Police Scotland had a two-week campaign during which thousands of drivers were stopped, and 280 were charged with drink-driving. This year 169 were charged, a 40 per cent drop.

However this year's initiative was accompanied by a prominent television and social media campaign launched by the force, warning of physical, lifestyle and career risks a driver is taking personally when they choose to drink and drive.

The emphasis in these has been that even a single drink is enough to put yourselves and others at risk if you venture behind the wheel.

This could be argued to have had a short-term effect of depressing the figures, leading some to wonder whether the change will be maintained.

The second question is how much of an impact policing in general has on any of this. The change in attitudes to drink-driving has regularly been cited as one of the great success stories, demonstrating that the social acceptance of an activity can be changed.

The opprobrium now attached to drink-driving was the model for changing attitudes to smoking and similar tactics are being used to change behaviours in other areas - to challenge the acceptance by some young males of the carrying of knives, for example.

However, the evidence that crackdowns and enforcement tactics make a difference is slim.

Across a whole range of offences and geographies, crime in Western Europe is broadly down, regardless of the political or policing climate.

We are simply becoming more law-abiding. The police need not claim too much credit for this. In the same way we are becoming safer and more safety conscious. That is one of the reasons why house fires, and deaths from them, have fallen to a 23-year low.

None of which undermines the fact any reduction in drink-driving is welcome.

Meanwhile, the Don't Risk It publicity campaign has another valuable role to play.

With the Scottish Government unable to act on its desire to cut the legal drink-drive limit, while it waits for the recalibration of breathalysers and other equipment, a "soft" cut dependent upon attitudes not enforcement could help prepare drivers for this significant change.

When the new 50 microgram blood-alcohol limit comes in, a pint of beer consumed will be enough to make driving illegal. That is a significant change, so persuading drivers to start thinking in these terms is an important development in its own right.