If someone is going to speed, they will speed. If you make a 40 a 20, they will still speed. So, signs as a general mean diddly squat in the real world. Had a pillock hurtle down our street this morning , which is heavy residential and a school, yet still tried to utilise his wing mirrors as wings to take off. I just lift my phone up and they think they are being recorded and the brakes soon come on ! As for the rozzers. I can see their point of view .Have a look at youtube and see what kind of morons are allowed to drive and how they ruin it for others. Sadly, they drive like that, they breed in a similar manner and carry on the stagnant gene pool.
We all wish to go and enjoy our cars , dont get me wrong and cant say I drive with the halo glowing, but there is a sensible place to do it , while some cant grasp that in the tattoo'd hands.