If Camden Council, The Guardian and the Lib-Dems agree on something it is almost certainly restrictive, dirigiste and mistaken. They are campaigning for 20mph speed limits. The European Citizen’s Initiative is praising councils calling for 20mph, “for residential streets with populations,” and no, I don’t know what that means either. Sounds like the woolly thinking of self-serving populists.
Nobody is against measures that reduce casualties yet the overwhelming evidence is that simply posting notices and passing laws do not always work. As recently as August the Department of Transport said casualties in 20mph zones had gone up, while those on 30mph roads had gone down. Portsmouth brought in a blanket 20mph limit in 2007. The numbers of killed and injured went up from 79 to 143.
The fact is that drivers don’t pay attention and pedestrians are complacent in “Twenty’s Plenty” zones. The behaviour of neither is commendable but laying down a law is not going to change things. Let’s go instead for what works, and the 85 percentile rule by and large does. Speed limits based on what 85 per cent of traffic thinks is about right, means that 85 per cent of it complies and the 15 per cent that don’t can be weeded out and punished. It is practical, it has been the rule since urban speed limits were brought in under the 1930 Road Traffic Act, and despite increasing traffic ever since, casualties have been steadily decreasing. We must have been doing something right. Let us not allow Camden Council, The Guardian and the Lib-Dems to make a mess now.