TO be the “slowest in Europe” would not normally be a national boast. But it might well become one if a bill to cut speed limits to 20mph in every village, town and city in Scotland is passed this year.

Green MSP Mark Ruskell’s planned bill is expected to receive enough cross-party support from MSPs to pass into legislation – though the Scottish Government’s position is to “keep an open mind” on a national scheme.

Many voices have been raised against the plan. Hauliers and business groups say it will drive up costs, which will ultimately be passed to the consumer. The scheme, it is said, will be difficult to enforce. Indeed, budget-pressed Police Scotland has said the limit will be “largely self-enforcing”. It’s also claimed that existing 20mph limits have not been respected; that increased pollution will result; that road rage and frustration have already been evident. Then there’s the cost: £5 million.

However, there’s strong evidence that a 20mph limit reduces casualties and deaths. In Edinburgh, where a 20mph limit is already extensively in place, these are down by 24 per cent. Police have noticed “calmer” driving.

As for pollution, there is some debate about this, as it varies between petrol and diesel vehicles. The hauliers might have a point, but surely most of their driving is done out of town? A 30mph lorry in town is not a good idea.

The price tag could be mitigated by the reduction in costs associated with casualties. And, indeed, we come back time and again to safety. A pedestrian is seven times more likely to survive being struck at 20mph than 30. At 20, drivers have more time to react. Studies have shown 20mph zones reducing child pedestrian accidents by 70 per cent.

We do understand that speed limits have to be credible. They cannot be seen to be spurious or vindictive on the back of a “four wheels bad, two wheels good” ideology. We also have concerns that a disrespected 20mph might bring other limits into disrepute, and we are not certain that 20mph is right for all suburban roads.

But, under the legislation, councils could keep some roads at 30 if they could make a case for these. Instead of a 30mph norm with 20mph exceptions, we’d have a 20mph norm with 30mph exceptions. Beyond all that, child safety trumps every argument. A price cannot be put on that.

The Scottish Government’s “open mind” hints at a preference for a national trial with subsequent review, which sounds wise – assuming the scheme were genuinely open to later modification. As for national boasts, these can sound awkwardly pawky. But, on this issue, slower speed could undoubtedly put Scotland ahead of the game.