diamond geezer

 Wednesday, January 18, 2012

Last week TfL announced they'd be making cycling-friendly improvements at the Bow Roundabout. Lots of people applauded. But at the moment they're only "potential improvements", subject to public consultation, and there are a couple of different options up for grabs. Today, let's look at option 1.
A cycle 'early-start' phase at the traffic signals on the eastbound and westbound entrance to the Bow roundabout. This would provide a dedicated green light phase to allow cyclists to travel ahead of other traffic.


On the face of it, this sounds like a great idea. Allow cyclists onto the Bow roundabout a few seconds ahead of vehicular traffic, and then no driver turning left can accidentally run them over. Temporal segregation is to be achieved with the aid of an advanced-stop line and some extra traffic lights, the combination of which will give cyclists a proper head start. TfL have kindly provided a video to help you understand how the redesigned layout might work. But while you watch it, keep a careful eye on the phasing of the various traffic lights. And then see if you agree with me that perhaps this isn't an ideal solution after all.

Here's what happens at the revised roundabout junction if you're a car driver.
If the main lights are red you stop at the stop line, just like you do now.
If the main lights are green you continue onto the roundabout, just like you do now.
If you're a car driver, essentially, nothing changes.

Here's what happens at the revised roundabout junction if you're a cyclist.

If the main lights are red then your light is green, so you pass through to the red light at the advanced stop line and wait there.
If the main lights are green then your light is red, so you have to stop while everyone else drives onto the roundabout.
If you're a cyclist, you always hit a red light.

So the new arrangements are safer for cyclists, but also slower for cyclists. They'll be held back while traffic alongside is moving, and they'll also have to be held back for several seconds beforehand to prevent cars, lorries and buses catching up from behind. Waiting at this new backstop light is unlikely to be an attractive option. Will cyclists behave and hold back, or will they be tempted ahead, either by jumping the red light in the cycle lane or by deviating into the main flow of forward-flowing traffic alongside? I wouldn't like to second guess which approach the majority of cyclists at a newly designed junction would take, but I bet many will ignore the additional red phase and advance to the front anyway.


Additional dedicated cycle lanes on the east and westbound approaches of the roundabout, allowing cyclists to approach the advance stop lines at the junctions without the need to filter through traffic.
TfL are pushing this "additional cycle lane" as a positive improvement, whereas in fact it's an admission that the current eastbound Cycle Superhighway 2 is wholly inadequate. At the moment, you may remember, CS2 is nothing but a painted stripe along half of one lane of queueing traffic, which means cyclists can't reach the existing blue-painted box. I blogged about this six months ago, calling the existing Advanced Stop Line "an inaccessible white elephant" - essentially an inexpensive "oh that'll do" solution. It's taken two dead cyclists for TfL to propose something they really ought to have done in the first place - carving a safe cycle lane out of the wide-enough pavement to provide proper segregation. Better late than never, TfL, but no thanks to the cheapskate/cretin who sanctioned the original design.



But, however good it sounds, there is something dangerously stupid about this new cycle lane. Less than ten metres from the entrance to the new cycle lane, there's a bus stop. If the bus stop's empty, no problem, cyclists can ride straight through into the new indented cycle lane directly ahead. But this is a bus stop served by approximately fifty buses an hour, so cyclists are more than likely going to find their onward progress blocked. They'll have to swing out into the traffic, as now, in order to avoid the big red obstruction. But then they'll have less than ten metres to nip back in again to join the new cycle lane. That's cyclists moving to the left, while the bus in the bus stop will be pulling out to the right across precisely the same piece of road. I don't know about you, but that sounds very dangerous to me.

So that's option 1. An extra red light for cyclists to wait at. A potential new accident blackspot between the bus stop and the new cycle lane. No change to the roundabout itself, only to the approach. And still absolutely bugger all to help us local pedestrians cross safely. Sorry, not impressed. I wonder whether option 2 might be any better...

» TfL consultation - Bow roundabout
» TfL press release- design proposals to further improve cycle safety at Bow roundabout
» Two videos: birdseye view, cyclist view
» Plan showing potential design for a cycle 'early start' at Bow roundabout
» reaction from cyclists


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