Speed is not the issue, it's the quality and standard of today's driving that's the problem.
Enforce with an iron fist the problems created by those who use mobile phones, a far greater threat than speed in my opinion. I drive a fair bit for my work and the amount of these morons, usually with BMW / Audi / Mercedes (hmm must be a German thing) that have a mobile stuck to their ear for miles on end drives me mental, I have a bloody van with factory fit bluetooth surely you can get one in a fekin high end motor!!!!!!!!!!!
Also stop people smoking when driving, drinking, eating etc etc. Too many variables inside the vehicle to deal with before chopping 10 mph of the local speeds. Due care and attention need improving first.
I recently went from CBT to DAS in a little over 2 months and got myself every book available regarding riding safely, having sat the theory test it's obvious something needs to be done. I would like to see a refresher driving test every 10 years max, a low cost version without a failure option, purely a revision and bad habit highlighting style test. You don't fail, you merely have to undergo further improvement training and also there should be a basic controls test whereby you have to be able to operate on a test rig a set of controls, steering, brakes etc with a certain amount of resistance determined by your age.
How many people (forgive me here) do see behind the wheel either to frail or two fat to operate the controls in an emergency situation. There should be a fitness test, might get some lard off those arses of some folk.
All in my humble opinion of course.
Steve.