Comment by grosun

You can drive through London for an hour in mostly 20mph (~30km/h) zones. Thing is, you're unlikely to be averaging anything even like 20. Even when the limit used to be 30 you weren't either. My old car averaged 16mph, & that included trips out of town at motorway speeds.

When the 20 limits were first introduced, lots of people would speed & overtake, but then you'd catch them up at the next traffic light & the one after etc.

I know London's quite an extreme case, but all a 20 limit means in a lot of stop/start urban areas is that you travel to the next stop at a speed which is less hazardous should you hit something/someone, with far more time to react to all the unpredictable things which happen in busy urban areas, thus decreasing the chances of hitting anything in the first place.

Yeah, it's mildly boring, but driving in cities pretty much always is. Just put on some music or a podcast and take it easy.