Except that cyclists aren't confined to the blue lanes and nor should they be. I don't like that the straight-on northbound cycle lane is left of the turn-left carriageway lanes because it looks like your last chance to overflow into the carriageway lanes might be a long way back at Magee Street, if that pink line means a stupid Bloomsbury-style kerb rather than something you can ride over.
Exactly. That cycle infrastructure will not accommodate the number of cyclists that will attempt to use it at peak times. People will use it, it will fill up, some will queue, some will jump the queue, some will bypass the cycle routes when they see they are busy, some will bypass the cycle routes as a matter of course. With this layout a cyclist would sensibly have to have made a decision on how to navigate this junction before they had passed the previous one (probably before they can see which route through is clearest), taken a position on the road and held it for 200-300m. The majority of people aren't going to be behave in such a clear cut disciplined manner. The infrastructure doesn't grant the flexibility to allow a mix of cyclists to navigate that junction safely.
A side note on the the cyclist's option to bypass the cycle infrastructure northbound - the three main traffic lanes have been reassigned from one turning left onto the A23 and two continuing straight on via the A3 to the other way round. Now, it's a regular occurrence as a cyclist to find oneself being bullied out of an attempt to use the centre lane to access the cycle lane and continue straight on. The provision of highly visible, disruptive cycle infrastructure while providing only one lane for all other traffic not using the cycle route on to the A3 isn't going to make that manoeuvre any easier to negotiate.
The current layout does have problems. Conflicts arise between those that wish to turn left and those that wish to continue straight on - this happens in both directions and isn't limited to solely cyclist/motorist interactions. These conflicts occur when streams diverge - the vehicles involved are initially travelling in the same direction and shouldn't have any conflict of priority; they do so when someone doesn't grant another road user the space and time one should expect. Dealing with this sort of conflict is part of the general awareness of travelling in a traffic stream, there are usually a few cues as to when a situation is developing. The resulting (hopefully) near miss is usually a squeeze.
The traffic streams with alternate priorities are held back at some distance and cross at right angles - visibility and awareness of any transgressor is pretty good - it's why many cyclists successfully RLJ.
The proposed layout separates different streams of traffic that originate from the same direction and then grants each stream different priorities as they cross each other. This means that if someone jumps a light or swaps lanes aggressively then they will come into conflict with those that are
i) already in close proximity
ii) probably less aware of the transgressors presence due to the acute angles involved
iii) more likely to collide as the streams cross at a sufficient enough angle to make a 'squeeze' less likely
The more complex arrangement will lead to more people making mistakes, more people deliberately flouting rules and laws and more opportunities for people to do so. Designing a junction in London without an awareness that this would be the case isn't feasible after Bow. This scheme is another whole area of fail.
"straight, consistent CS7"??? Straight except that it hops lanes and consistent except that it suddenly vanishes from a cycle-only lane and reappears in an adjacent shared lane?
The 850m of CS7 that continues on Kennington Park Road in a straight line, in the same lane, at the same width, with the same status broken only by markings for pedestrian crossings and bus stops. That bit.
But so much for just kicking it, long after the consultation has passed. I ask again: what would be the best solution there?
I think I would have preferred a layout more like the about-to-be-replaced layout of the Hills Road bridge in Cambridge
http://cambridge.cyclestreets.net/location/48831/ where the turn-left lane has to give way to crossing cycle lane traffic, but I doubt that's popular on CC.
The Cambridge solution is pretty similar to the current northbound arrangement on the A3. The problem is scale, variety and complexity. The London junction carries more traffic, in more lanes, that backs up further. Its requirements change drastically through the day. There are other large junctions in close proximity and rush hour motor vehicle capacity will have knock on effects for miles in several directions. It's a symptom of London's unwieldy road system that was first bolloxed when the Romans decided to move London Bridge. I don't think that there is a hard infrastructure solution that will work in the space available. Banning turns and regulating traffic flows is one option (which this proposed layout does, and I can imagine that being the only solution to one of the essential requirements for this scheme - stop the repeated killing of cyclists outside Oval tube station). But I think such measures need to be far more robustly implemented. Brixton is an example where this has been done extensively, and for some distance from the centre, but for the sake of congestion management though.
Dare I say it, but paint, oodles of coloured paint that designates pretty much the whole junction as a mandatory cycle lane during rush hour might be the solution that offers flexibility. If mandatory cycle lanes were more like bus lanes in London that would be a game changer. Bus lanes are observed religiously because of enforcement. Many motorists don't even use them outside their hours of operation. Enforced mandatory cycle lanes would boost the effectiveness of advisory lanes as well. Both should have a minimum width of one standard traffic lane, it would make for a far more pleasant cycling experience - newcomer to old hand alike.