This is exactly my issue. I'm not against 20mph in urban areas, but 20mph limits on roads that are clearly designed for 30mph (or more) are a lazy solution. Every subconscious instinct of an experienced driver on these roads will be telling them to drive at 30 so they have to consciously focus on the speedometer to stay within the lower limit for prolonged periods, particularly with the proliferation of speed cameras we have in the UK - my fear in a 20 zone is often now that I'm going to cause an accident because I'm so focused on the speedometer and not the road.

The right solution is to actually turn these roads into 20mph roads (not 30mph with 20mph limits) through simple road design measures that will align drivers' subconscious perception of the road with the speed the government wants them to drive at. I recognise that this can't happen overnight but I see no effort by local or national government to even start investing in the set of changes needed to make 20mph sustainable. If these roads just felt like 20mph roads then people would be a lot less annoyed at driving within the speed limit and the government wouldn't just be stoking up a massive political backlash that will end up returning them all to 30mph and abandoning all the road safety and air quality benefits that these policies are supposed to deliver for us.