Wales’s 20mph speed limit saves lives and money. So why has it become a culture-war battlefield? | Will Hayward

In September 2023 the Welsh government introduced the default 20mph speed limit in Wales .

A petition on the Senedd website opposing the new measures has reached nearly 470,000 signatures.

Protests sprang up citing the cost of the policy ( 32 m, mostly on changing road signs and markings) Many of the 20mph signs were vandalised, meaning they had to be replaced at additional cost.

On roads affected by the change there were 10 fewer deaths compared with the previous period, saving 24 m.

The Welsh government has been far from flawless in its implementation of the policy.

The experience in Wales is a lesson for the wider UK and beyond.

Evidence-based policy does work, but you have to own it, explain it and stay the course.

It costs political capital, and politicians need to be brave.