But twenty isn't plenty. If you can't drive at a steady thirty miles per hour, assuming decent weather conditions, without fear of an accident then you don't deserve your licence. Bearing in mind most speedometers show 30 miles an hour when the car is physically travelling at 26 miles an hour. When the "twenty is plenty" numpties drive at an indicated twenty miles an hour they are actually driving at about 17 or 18 miles an hour. I WILL OVERTAKE YOU!!!!!!!!
Do not forget, some people have a 50 mile commute. For any number of reasons moving may not be an option (and in some instances if they gave up the work, hundreds of people could lose their jobs). They cannot take a horse or bike, there isn't public transport, and every minute on the way home stuck behind someone who is incapable of driving at the legal speed limit is a minute they are being needlessly kept them from their families. THEY WILL OVERTAKE YOU!!!!!!!!!
In both those instances, the party overtaking is not some reckless criminal but probably someone who has driven at 30 mph (perhaps even an indicated 33 mph ;-) on various occasions over a few years who has never knocked over a child, dog, horse etc. Please don't try to marginalise otherwise law abiding citizens for no good reason.
Nothing will stop the idiot who, as has been said before, ignores the speed limit. Driving at 20 just gives them more opportunities to put my life, your life, and our respective friends and families life in danger. Please do not confuse the 2 - and drive at 30 miles per hour.
Thank you.