LOOKING back at the early years of the Scottish Parliament, the small changes in the law that initially raised eyebrows are now accepted as important shifts where Scotland led the way.

The ban on smoking in public places is perhaps the most striking example. Public opinion was divided when the ban was first mooted and while most accepted the link between smoking and ill health, questions flew over how this policy was actually going to work and be enforced.

To a large extent the ban became self-policing as we passed the tipping point of public acceptance. Today the ban is widely acknowledged as a great success and we can hardly remember a time when smoke filled bars and buses.

Loading article content

I believe we are at a similar point now with road safety and the speed of traffic in our residential areas. The link between increased speed and road casualty rates is well proven. Road traffic injuries are the top global cause of death for those aged 15 to 29, and driving at 20mph prevents 20 per cent of casualties. At this speed, victims are seven times more likely to survive.

However, we still have 30mph limits in most streets where children play. The 30mph limit was set in the 1930s at a time when our understanding of road safety was very different, not to mention drastically lower traffic levels.

Growing numbers of streets are being exempted today from the default 30mph speed limit to create safer 20mph zones. They have been popular too, with many community campaigns springing up to demand them. On the ground, some councils like Clackmannanshire are going for a switch to 20mph limits in all residential areas, while others such as Falkirk only have part-time zones outside school gates. Not everyone is fortunate enough to live next to a school. But part of the challenge councils face is the lengthy legal process it takes to set up patchworks of 20mph zones. The result is a postcode lottery of protection across Scotland.

For these reasons and many more I believe the time has come to flip the default speed limit in urban areas from 30mph to 20mph and I’ll be introducing a Member’s Bill at Holyrood to attempt this in the months to come.

To be successful, any switch would need a major national publicity campaign, but there would also still be a strong role for councils in shaping the scheme on the ground.

As City of Edinburgh Council acknowledged in its city-wide 20mph scheme, there will be main roads that need to stay as 30mph to aid traffic flow and the same will go for some rural roads passing through village centres. However, these should be the exception rather than the rule and the benefits of a default national 20mph limit should be felt across most places where we live.

Speed reduction measures such as rumble strips, road narrowing and flashing signs may still be needed in speeding hotspots, but these measures alongside speed humps are mostly used to mark the entry to 20mph zones at present. Drop speed overall across a larger residential area and there is less need for expensive humps – and it also becomes easier for the police to enforce on longer roads.

There would be many other benefits to our communities. Studies show that particulates and nitrous oxide from diesel engines are reduced at lower speeds and when thousands die every year from air pollution we need to do everything we can to avert this health crisis. That’s another reason why organisations like the British Heart Foundation and the British Lung Foundation are backing my Bill. It’s also why the Royal College of Paediatrics and Child Health recently backed the rolling out of 20mph limits in our streets.

Of course there’s a wider health benefit to our streets feeling safer and breathing easier in that it encourages walking and cycling. Evidence from cities that have gone 20mph like Bristol show positive feedback. Dropping speed isn’t the only thing we need to do to encourage cycling as quality segregated cycle routes as well as training and promotion are also important.

But, given that speed limits are a newly devolved power that has now come to Holyrood, reducing the speed of traffic outside our front doors would be a great first step to building much safer and healthier communities.