Why 20mph isn’t going to work in Blackfriars, or anywhere else for that matter …
Why isn’t TfL keen on 20mph zones at Blackfriars? Last night I attended my local Police Liaison Group and earlier in the week, I went to the council’s Cycling Liaison Group.
20mph zones came up at both of them, but it was only the Sergeant at the Police Liaison Group who turned up with the key nugget of information: the Police can’t enforce 20mph zones, so they either need to be self-enforcing (i.e. nice signs, and trusting road users to do the right thing), or they need sufficient traffic calming to effectively make more than 20mph unpleasant for drivers.
With TfL’s near messianic obsession with traffic calming, and the clear evidence from Blackfriars that they want traffic (which doesn’t really seem to massively include pedestrians or cyclists) to move smoothly and quickly through the junction, you’d think they wouldn’t bother looking for excuses to thumb their noses at a group who can be majority users on the bridge. But if it’s true that the Police can’t legally enforce a 20mph zone, then it’s certainly possible to see the argument that it’ hard to design for it.
Apparently the issue is not to do with the equipment available, but the specific speed: the Police are apparently only able to enforce a 30mph limit, and can’t even use rules like dangerous driving / reckless driving in 20mph zones, unless that is evidently present (i.e. driving at 30mph in a 20mph zone is not a prima facie piece of ‘reckless driving’, for example).