What's the point in this road furniture?

On Brockley Grove, there is this single bit in the road that seems to just be there to force cars closer together (they never slow down though as it's still just wide enough for 2 cars) and no gap for bikes to go along the side instead of through the middle.

http://bit.ly/89T77S
(should open google streetview)

Almost been clipped by bellends charging through it quite a number of times, I just don't understand for the need of the side bits squeezing the road smaller, it doesn't slow people down any more than just having the humps on the road.

Am I missing it's purpose?

There are several different possibilities as to what drove this scheme. It looks to me as if that street can be quite difficult to cross at peak times, and that this measure aimed to shorten the crossing distance. The one further down past Elsiemaud Road provides a pedestrian refuge. There may also have been an intention to slow motor traffic down, although both spots are rather poorly executed--textbook measures that aren't really in tune with the local context of the street. It's also possible that there may have been crashes there, perhaps at the junction with Elsiemaud Road, and that this was a Local Safety Scheme designed to reduce speeds past that junction. However, the pinch point isn't very well designed. When you approach it, check over your shoulder (not just a quick furtive glance, but a proper look) and try to make eye contact with following drivers. Then use your judgement, e.g. if they react by slowing down, to position yourself in the centre of the lane. Don't hesitate to ride over the cushion--hold your position until you're past this point.

Yeah it's an odd one, I don't think it's really in place to help peds cross as around 100 yards up the road the other way is a properly designed crossing:

http://bit.ly/8Ctcmr

the wisdom of local councils eh?

^ That's a weird one. Encouraging people getting off the bus to cross right in front of it.

Yeah it's an odd one, I don't think it's really in place to help peds cross as around 100 yards up the road the other way is a properly designed crossing:

http://bit.ly/8Ctcmr

the wisdom of local councils eh?

Yes, that's the other one that I referred to in my earlier post. Those would both have been part of the same scheme. Both are designed to increase pedestrian amenity (although neither are 'proper' crossings, i.e. zebras or pelicans/puffins).

Pedestrian crossings can't be too far apart to be effective, as people will just try to cross, anyway, if they have to walk too far.

^ That's a weird one. Encouraging people getting the bus to cross right in front of it.

Sounds about right for a council traffic scheme. I've nearly hit several people walking out from behind the front of a bus.
I'd love to know (but not enough to actually lookup) what research was done into the effectiveness of humps and chicanes in different contexts, and how often the schemes are re-evaluated after they have been implemented. Most of them seem to only anger motorists, endanger cyclists and confuse pedestrians, and even in my most cynical moments I can't believe that is what was intended.

I believe they are designed to ensure that people don't drive around the humps. At least it is not the lovely suicide lane (where two lanes are forced into one just to make things interesting).

it's to slow down traffic. it's an exceptionally wide single-lane carriageway, the narrowing would take a car doing 80 down to 50 or 60. also, it's hinder people trying to overtake.

maybe it's a chicane designed for collision spotters?

speed trap??

I've wondered about that one as well - as far as I can see it achieves nothing positive and, like so many "calming" measures, just encourages people to drive unsafely. Brockley Grove is a funny road, as there's not a great deal of traffic; the north side has the cemetery and the roads on the south side are generally very quiet, so the drivers of vehicles on B Grove itself have very little to make them behave cautiously.

While some speed cushions encourage people to swerve to avoid having to slow down, this one encourages drivers to ride without regard for other road users by narrowing the track that they must follow unless they're prepared to slow down, which most aren't.

There was a great bit of street furniture on Southwark Bridge this morning: someone had mounted the paved cycle protection kerb and three wheels of their white van were in the air

Not exactly an unusual arrangement though, this, surely? You see stuff like this pretty much everywhere.

There was a great bit of street furniture on Southwark Bridge this morning: someone had mounted the paved cycle protection kerb and three wheels of their white van were in the air

That kerb is actually put there to protect the bridge structure against someone crashing against the railings; as it's listed, they couldn't think of any other way of doing it than by sticking that kerb down quite far away from it. Looks as if it's done its job this time. Apparently, if a car crashed against the bridge railings, it would go right through.