"One of the key figures in the rise of 20mph speed limits in the United Kingdom is Ben Hamilton-Baillie, an architect, urban planner and traffic consultant whose work and research was influential in moves such as the one by Islington Council in October to limit all of its managed roads to 20mph. Islington claims a 65 per cent fall in accidents in its 20mph areas.
As part of research into how pedestrians and cars can share outdoor space more safely, Mr Hamilton-Baillie spoke to cranial pathologists who showed him statistics proving that the risk of mortality from a car collision isn't just linear â€“ it accelerates significantly after 20mph.
The explanation is that the human skull has evolved to withstand impacts up to around 20mph because that's about as fast as a human can run into something. It's also easier to keep traffic flowing at 20mph as a road with a 40mph limit will need extensive safety controls."
Why not here?