It’s simple, slower driving speeds save lives.

That is why I am really pleased that next month we will see the biggest change in road safety for a generation with the introduction of a 20mph default speed limit on restricted roads across Wales from Sunday, September 17.

Twenty people are killed or seriously injured on Welsh roads every week, according to the latest police recorded collision data. That’s more than 1,000 lives lost or seriously affected by collisions every year, with huge impacts on their families and friends.

In recent weeks, I have received a number of emails from constituents both for and against the change. So I am using my column this month to explain why I support the legislation.

I voted in favour of the 20mph legislation when it was passed in the Senedd in 2022.

It was a manifesto commitment in the Senedd elections in 2021 and is therefore part of the programme for government I was elected on.

Easily the biggest argument for the 20mph limit is around safety.

The evidence is clear, decreasing speeds reduces collisions and saves lives. People are around five times more likely to be killed when hit by a vehicle travelling at 30mph than a vehicle travelling at 20mph.

Making the change from 30mph to 20mph could result in 40 per cent fewer collisions every year, with six to 10 lives saved and between 1,200 to 2,000 people avoiding injury.

Add those up and it is likely we would save up to 100 lives over the next ten years and prevent up to 20,000 people being injured.

These are big numbers. It is estimated that in casualty prevention the new legislation would save around £92m in the first year alone.

Reducing speeds not only saves lives, but helps us to build stronger, safer communities.

Evidence from across the world shows that vehicle speed is one of the main reasons why people do not walk or cycle, with one in three Welsh adults saying that 20mph would increase their likelihood to walk or cycle more.

So, not only will slower speeds save lives and reduce injuries, it will also help to keep people healthier and reduce the burden on the NHS.

While most default 30mph roads will automatically reduce to 20mph, local councils have the flexibility to make exceptions and keep 30mph speed limits on certain roads.

Torfaen Council has applied for 36 exceptions which will remain 30mph for 18 months while a review is under way. You can see the list of 30mph exceptions on its website.

It's estimated travelling at 20mph will add just one minute per mile to car journeys but it will add so much more to the safety of our communities. That is why I support it.