You only prove my point. The fixation on speed is (in at least some cases) downright dangerous. A road not too far from where I live was accident-free for about two decades ... until the local authority made it a 20mph zone and installed 'traffic calming'. Within a few months a young boy was knocked over and crippled. The person who told me about the case related that the driver had claimed the boy had just run out in front of her car and she hadn't spotted the danger because she was concentrating so hard on negotiating the traffic calming measures and ensuring she was doing 20mph. RTCs now occur regularly along that road. In another case, a woman collided with the rear of a car that was emerging from a side road. Partly to blame was the council for installing a build-out that forced the emerging car to take a position where it was obscured by a wall and also where the driver had limited visibility. The woman who had 'right of way' claimed she couldn't possibly bear any blame because she was obeying the speed limit! She hit the rear of the emerging car -- so she would have had time to stop if only she had used COAST to assess the situation and adjust her driving accordingly. A hundred yards or so from that scene is another where the brain-dead council (in the interest of 'road safety') installed a build-out that reduces the carriageway width so that a large vehicle emerging can't clear fully -- and I now regularly see broken glass and other evidence of collisions where few, if any, previously occurred. The establishment fixating on speed sends a very dangerous message -- that all you need do to be a 'safe, good driver' is obey the speed limit...
Speed is a very dangerous proxy for road safety. Of course, you shouldn't bust the speed limit as that's against the law. However, rely solely on the speed limit and bad stuff is inevitable; drive with COAST and bad stuff is much, much less likely.