It's already happening, like it or not...Gradually being 'encouraged' out of our vehicles. Regardless of your views (good or bad idea) it's happening and will only increase. I reckon some of the stuff being implemented in cities will eventually find its way to larger and perhaps smaller towns. Oxford setting up separate zones, encouraging people with cars to remain within their own zone where possible.
All the towns and cities in Britain with planned clean driving zones
Under government orders, councils have been told to curb their air pollution levels - and to do so, they should rid roads of the dirtiest cars, meaning clean zones are coming.
www.thisismoney.co.uk
I don't think the majority are yet aware of what's going on.
Currently some do or don't affect private cars, but this may change over time. Some of the daily fees are pretty big, they could soon mount up. Scotland is £60 reduced to £30 for a car, but then doubling each time you re-offend to a maximum of £480.
It's only a matter of time before the non-compliant cars lose lots of value, this doesn't seem to have happened yet from what I've seen so if you have one then now's a good time to make it someone else's problem - flog it and buy a slightly newer one, while it won't currently cost a vast amount to do so. This has probably already happened with vans, it's probably too late to upgrade a van now without paying a vast amount to trade up.