Fact Check: Cost of Welsh 20mph policy estimated at £4.5 billion

Wales introduced a default 20mph speed limit on restricted roads—typically in residential and built-up areas—under the Restricted Roads Order 2022, which took effect in September 2023. The Welsh Government justified the change as a measure to reduce collisions, encourage walking and cycling, and improve public health and street safety. A 2022 explanatory memorandum from the Welsh Government estimated the policy’s direct financial cost to the government at £33 million, including £29 million for implementation in 2022 and 2023. However, the wider economic impact was projected to be largely negative due to increased journey times for businesses and households, with a central estimate of £6.4 billion in disbenefits over 30 years (2023–2052). The memorandum acknowledged significant uncertainty, with potential costs ranging from £2.7 billion to £8.9 billion. When accounting for benefits such as improved road safety (worth £1.4 billion) and environmental and health gains (worth £0.5 billion), the net estimated cost of the policy over 30 years is £4.5 billion. The Welsh Conservatives have highlighted the upper end of the cost range (£8.9 billion) in their criticism, despite the Welsh Government’s emphasis on the net figure. The policy applies to roads previously limited to 30mph, now designated as restricted roads under the new rules. The Welsh Government maintains the changes will make streets safer and promote active travel, though the economic trade-offs remain a point of debate.