Leader Comment: Strong case needed for 20mph limit

Support for 'safer driving' is incontrovertible. There is a universal wish to see fatalities and serious accidents reduced on Scotland's roads. But is imposing a 20mph speed limit in our towns and cities an effective way of achieving this?

The 20mph speed limit has already been rolled out in parts of Edinburgh. Picture Ian Rutherford

The Greens think so. They say the current system is a “postcode lottery”. Speed restrictions vary from one town to another and often between one area and another in the same city. This has bred confusion as to what the speed limit is. So the Greens are proposing new laws which would enforce 20mph zones on built-up areas across Scotland. They say the Scottish Government has not moved fast enough to protect children and the elderly put at risk of injury.

It is a compelling argument. Drivers may sigh in despair at the prospect of yet more laws and restrictions. However, average speeds in many city centres are already down to 20mph because of the sheer volume of traffic. Areas where drivers are cautioned to slow down are already well signposted. A blanket 20mph limit removes even more of the drivers’ discretion to proceed carefully – the assumption being that only laws and proscriptions achieve this result. It makes no allowance for emergency vehicles. It imposes further duties on the police. And it is unlikely to deter the truly irresponsible.

The case needs to be underpinned with compelling evidence showing that the number and severity of accidents where a 20mph limit is in operation is significantly below those where the operating speed limit has been kept at 30mph. That evidence also needs to cover areas in the approach to 20mph limits as drivers may be tempted to accelerate before entering the area.