impact speed of 40mph or anything close.
I witnessed an accident when a pedestrian was probably hit at ~40mph. A don't do. Late night, gets off a bus, exit at front, in a hurry and simply runs out in front of the bus. Traffic was light. He sailed into the air and finished up with some serious fractures, Very serious but lived. At the time to me the bloke was old so probably ~50 or so. Bones don't repair so well as we get older. The insurance company concerned was rather bothered about the amount they were going to have to pay out.
The same number cropped up when I needed something cheap to get to work. 2 wheels. Dad asked grand dad - policeman. He asked about the bike exceeding 40mph and mentioned that a crash helmet helped a lot but pointing out that collisions at speeds in excess of this are often rather serious. They can be very at 40 depends on what you hit.
Dad turned up with a motor scooter. I would have bought a bike.
Work. Data gathering. Does stuff remain in place during "brick wall" collisions, Dead solid things, Not much interest over 40mph as people wont survive. TBH I doubt if that has changed much. Certain aspects have been designed out and in but there are limits. Some one managed to hit a rather solid tree in a modern car a few doors up from me, early hours. Nothing fancy about the car, Result dead. No doubt he used his brakes, Speed no one really knows but given the road I doubt it would be that high. Given what people do at this time of day I'd suspect ~50. 30mph limit. 40 rather commen at all times if conditions allow, Busy road. Not often but ambulances crop up now and again.
The 30, 40, 60 and 70mph limits will have been derived on this style of reasoning. 60's are an odd ball as there are roads where no one is likely to get to that speed. In some cases where they will 50 is introduced. Reasons may be due to bends and people getting it wrong or maybe it's the precautionary principle. All sorts of mights and bound to be better. 20mph is sounding a bit like this to me but this speed is likely to lessen damage to pedestrians. Other aspects - well vehicles will stop more quickly.
Implementation. A local county had the intent to set all 60 limits to 50. It didn't happen. Wales and 20mph. Tricky they have and haven't since they announced tell us where you want them but they have put some signs up and some people, not many are sticking to 20 where there are no signs. Often there is good reason to wonder why 20 has been set. They are also starting to change some 60's to 50. An outstanding example of this sort of thing is the work on the heads of the valley road. A new section, motorway class, no islands proper entrances and exits and they have stuck a 50 limit on it, Similar sections completed earlier are 70. One has as a few islands so speed limits as they are approached,
I feel the precautionary principle has been strong for some time in Wales. Looks like some areas in England are going the same way. It's hard to argue against it. Effectiveness though - I wonder. Different aspect, Counties often respond to serious accidents via road works. Motorways spring to mind. Some are one offs and I wonder if the next one off will be prevented?
