Institute of Welsh Affairs calls for national 20mph urban default

The Institute of Welsh Affairs in its recent report on “Decarbonising Transport in Wales”[1] has called for a default 20mph urban limit as a key recommendation to enable Wales to meet its projected energy demands entirely by 2035.



The report notes in its foreward that:-

Decarbonising transport will make a huge contribution to Wales’ success in meeting its projected energy demands entirely from renewable sources by 2035. The transport sector has considerable potential to address pressing concerns relating to health, the economy, climate change and equality. Transport also has a massive impact on the way we plan our lives; more sustainable choices could be our route to a healthier and happier lifestyle.”

With regard to 20mph limits the report states :-

“Speed limits of 20mph have been shown to have a significant impact on the extent of injuries arising from collisions between motor vehicles and pedestrians or cyclists. Slower traffic also encourages more people to take up walking and cycling as the perceived danger from traffic is reduced.”


“A report by Public Health Wales[1] examined the case for 20mph speed limits in the context of the Well-being of Future Generations Act goals. It included a table assessing the range of benefits:

Table 5: The case for 20mph speed limits

Road traffic casualties 

  • Decreases in injuries, crashes, pedestrian and child pedestrian injuries of 17 to 70%

Air pollution                               

  • 12% reduction in gear changes, 14% in braking and 12% in fuel use; transport emissions reduced in residential areas by 12%
  • 32% reduction in NOx when average speeds drop from 31 to 19mph
  • 48% reduction in NOx emissions with a calmer driving style
  • Acceleration accounts for 35-55% of pollutants
  • Decrease in NOx emissions of 24-31%                                                                                                                   

Active travel

  • 12-25% increase in walking and cycling (Bristol)
  • Three fold increase in cycling to schools (Edinburgh)                                                                                                                   


  • 2dB reduction in traffic noise


  • Narrowed, differences across areas equalised

Social inclusion                          

  • Improved and enhanced

Community cohesion               

  • Increased, communities improved

Local business viability             

  • Improved; people using active travel to visit shops spend more money”

The Institute of Welsh Affairs report recommended that “Welsh Government should impose a default 20mph limit in urban areas, allowing local authorities discretion in exempting routes where justified.

Rod King MBE, Founder and Campaign Director for 20’s Plenty for Us commented :-

“We agree. Wales clearly has aspirations in Well-Being, Public Health and Energy Savings that a default 20mph limit can address. It now has the devolved power to set a national 20mph limit. Our forthcoming 20’s Plenty for Wales for Healthy and Liveable Streets[2]conference on Oct 2nd in Cardiff will be an excellent opportunity to learn why and how this could be accomplished.”

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