Average speed report from 1936

[Chris KC]

In Cambridge, where we have 20mph zones in (some, not all?) side streets, the argument has been that a pedesrtian is more likely to survive a collision with a car at the lower speeds..

Exactly so Hugh - the chances of surviving an impact are dramatically improved if the speed is reduced by 30% (or even more for 90%...) However as others have said, 20mph on a good road actually requires greatly increased concentration on the speedo (and less on the road), and also rather increases the risk of the driver zoning out at the wheel through sheer boredom.

I could understand if it was done at peak times on busy high streets - but the allocation of zones does not (I cite Bedford's case) match risk. Nor does it need to be 24/7 - e.g. 20mph outside schools at certain times of day I can understand.