Living in North Cardiff I have come to accept its use sadly it creates other behaviours when folk get onto a larger stretch of road they immediately push onto higher speeds .

There's a lot written about its benefit to the environment and road casualties but no real impact proof.

Reduced speeds can cause excessive engine idling which in my humble view creates as much harmful chemicals, gases and particle pollution, I think the 50mph Newport limit is barmy .

20 mph through heavily built up areas like Ely is a good thing for the elderly, disabled and children .

Sadly a lot of road causilties are in deprived areas according to one report I read, suggesting care for others is not always a number one priority for some ?