A study by Edinburgh Napier University has shown that the rollout of 20mph speed limits across the Scottish Borders has reduced average speeds by 3mph.

With previous research showing that there is an average 4% reduction in collisions with each 1mph reduction in average speed on rural roads, the study demonstrates the significant knock-on effect the new speed limit is likely to have, particularly when seen within the context of the national Road Safety Framework to reduce deaths and serious injuries to zero by 2050.

The trial, which took place across 97 villages and towns in the Borders since October 2020, showed that 85% of drivers dropped their speed by 3mph. It also showed that the largest speed reductions were observed in locations where higher speeds had been seen in the past – with those areas seeing an average reduction of 5.4mph.

Significantly, the report also concluded that the change in driver behaviour continued well after the beginning of the trial, with average speeds still well below previous levels eight months after the start of the trial.

The trial in the Borders is the first one in the world to look at the effects of a 20mph speed limit on such a large, rural area and the results will be studied by governments, local authorities and organisations across the UK and the world.

The study also comes just days before the Welsh Government is due to make Wales the first nation in the UK to adopt 20mph as the default speed limit on restricted roads – generally roads that are located in residential and built-up areas where there are significant numbers of pedestrians.

Professor Adrian Davis of Edinburgh Napier’s Transport Research Institute who led the research said:

“Previous research has shown that 20mph speed limits are effective in large towns and cities in both reducing speed driven and in reducing casualties. Our work looking at speed changes reveals that speed reduction to 20mph from 30mph in rural settlements produces similar results for speed reduction as in urban areas. Communities which have been asking for action to reduce speeding have been given a response, in this case by Scottish Borders Council who have taken action to address the dangerous and anti-social impacts of inappropriate speed. Our research findings consequently support the switch in Wales this coming Sunday from default 30mph to default 20mph speed limits.”

Link to report: https://blogs.napier.ac.uk/tri/technical-papers/