HAVING experienced, and enjoyed the novel experience of, the 20 mph speed limit in Islington, London, some two-and-a-half years ago, Iain Macwhirter wrote in these pages that such a limit, like speed cameras, was not there to punish motorists or provide revenue for local government “but to save lives, improve the quality of life and have traffic moving quickly. It’s not social engineering.”

Research publicised last February said that more than four lives a year have been saved since the launch of 20mph zones across Bristol. The report’s lead author said the scheme was a model for towns and cities across the world that were seeking to reduce traffic speeds and road traffic casualties, and promote community health and wellbeing.

Several cities have launched or experimented with 20 mph limits or zones in built-up areas, and pressure is growing for Scotland as a whole to follow suit. The Faculty of Public Health in Scotland is the latest organisation to support such a move, arguing that it would reduce the number and severity of traffic casualties.

The Royal College of Paediatrics and Child Health, keen to encourage greater physical activity among the young, has called on local authorities to introduce 20 mph speed limits in built-up areas to create safe places for children to walk, cycle and play. City of Edinburgh Council says a pedestrian is seven times more likely to survive if hit by a car driving at 20mph compared to 30mph.

The Glasgow Centre for Population Health (GCPH) has spoken of 20mph limits in Scottish urban settings achieving annual savings of between £7.8 million and £39.9 million while making roads safer and improving air quality.

All of which makes the Holyrood Member’s Bill launched by the Green MSP Mark Ruskell worthy of public support. It will allow MSPs to vote on whether the default speed limit in built-up areas should be lowered from 30 to 20mph.

The measure deserves to succeed but it is as well to bear in mind the GCPH observation: success will be impacted by different local contexts and by effective communication and behaviour-change campaigns and supportive policing and enforcement. The case for 20mph limits cannot be overstated, but the same surely applies of the importance of provisions such as these.