I live in one of the pilot areas so we've had this for a year now. It has been far from popular and remains so. For many reasons. Mostly because, no, they haven't limited it to only roads in residential areas. They kept one road only through our town at 30mph. The other main roads in and out were taken down to 20mph regardless of how built up they were.
And come tomorrow, they are even taking that one remaining 30mph road down to 20 until they then jump through the hoops of applying exceptions to this to revert it to 30mph.
It is costing a hideous amount of millions of £ in a time when cost of living is not good and the Welsh NHS struggles even more than England to keep to targets.
You can't overtake cyclists without speeding over the limit. It only adds one minute to your journey if your journey is one mile long. If you were driving for 60 miles on those roads, then you'd now be driving for 3 hours, not 2. They say that it lowers emmisions, but how can running your car for a 1/3 longer for every journey do that?
The first few months had many road rage incidents.
And, most worryingly, you have far more pedestrians stepping out into the road assuming that they have so much more time to cross safely, and often basically assuming you'll stop for them.
In a year the average speed on the roads here has dropped from 33mph when we had a 30 limit to 27mph in a 20.
Waste of time, resources and money.