Monday 16 January 2012

Lessons for Bow Roundabout from an older junction design

An aspiration for London
Several bloggers have covered that London is considering changes to the very busy and lethal Bow roundabout. Their website says that they are "redesigning cycle facilities at Bow roundabout, East London, to improve safety for cyclists."

I first saw this image a few minutes after returning from the centre of Assen. As it happens, on our most direct route to the centre of the city, I pass a junction which looks remarkably similar to a mirror image of what is being proposed in London and I thought I had to write about the similarity.

Real life in Assen. At first glance an almost
exact mirror image of the Bow proposal.
However, these two junctions are not as similar as they look. The junction in Assen works because proper cycle paths lead into itn and because it's on a relatively lightly used street. This area is nowhere near so busy as Bow roundabout. The raised kerb between the cycle-path and road protects cyclists at the junction instead of disappearing just before it.

The Assen junction solves problems which the London junction will suffer from - notably the ability of drivers to intimidate cyclists and to turn across their paths. The design in London requires drivers to turn left immediately after the traffic lights, crossing the route of cyclists, in order to reach some destinations. Cyclists in London are also encouraged to take up position at the right in a wide bike box depending in order to turn across the motor vehicles to make a right turn.

London's junction actually has two sets of traffic light, virtually guaranteeing a red light for approaching cyclists in a vain attempt to make sure any bikes in this location get away before the cars. Assen's junction completely removes all conflict.

The Assen junction is not part of a roundabout. At no roundabout in Assen are cyclists expected to mix with motor vehicles. No Assen roundabouts have lanes on road. Not one of them include a bike box. Not one of them puts cyclists in a position such as is proposed in London.

I don't much like advanced stop lines (aka "bike boxes"). Cyclists filtering through traffic to reach a bike box can find themselves an unpleasant situation on the wrong side of turning vehicles when the lights change. They can be subject to intimidation by drivers behind them, and upon reaching the bike box a cyclist can find that it is already full of cars or motorbikes. On a small road with few motor vehicles, they can just about work. On a multi-lane road like this, there are far too many points of conflict where cyclists and drivers will have to cross each others' paths and they should not be considered. It's a world away from sustainable safety principles which remove conflict and makes roads self explanatory in order to reduce the chance of collision.

Bow redesign includes plenty of scope for conflict between cyclists and drivers "sharing" a giant roundabout together.  Not only the routes but also the speeds are different, leading to many points of conflict.
Bike boxes are still sometimes seen as aspirational in other parts of the world, but far from being an ideal to aim for, they're actually one of the least effective measures that can be taken for cyclists. Bike boxes are increasingly uncommon in the Netherlands. I'm happy to say that we don't have any bike boxes in Assen. Therefore, the junction which I'm comparing with is different in many ways. However, it's the closest thing I can find locally to what is being proposed in London.

And that brings us to perhaps the most important difference between these two junctions. While the mega-city of London sees it as aspirational to install a badly designed junction like this on a roundabout on an incredibly busy and complex junction to give cyclists a very slight advantage on a route which is for some reason called a "cycling superhighway", plans are afoot in small towns right across the Netherlands to remove older infrastructure like the Assen junction and make further improvements to remove conflict and give cyclists more convenient routes. This is happening in the Netherlands even on small junctions like this.

Bike boxes are not something which should still be part of new designs, especially on busy junctions. Rather, they're an idea which both campaigners and planners should be looking beyond.

Lessons still need to be learned even from what will soon be removed in the Netherlands, so I've documented some details of the junction in Assen below, showing why this junction, despite its age, actually works quite well:

Cyclists stop 13 m ahead of drivers. Click photo for larger size
Fundamentally important is that paths taken by cyclists and drivers on the junction in Assen do not cross. There is no conflict here at all, and that's why it's safe. Only cyclists can make right turns and only drivers can make left turns at this location (cyclist left turns are at the previous or next junctions which drivers can't use in the same way):
All conflict is removed at this junction (some appears slightly later on, but it's certainly not comparable with Bow roundabout)
The video shows how the junction works in practice:

Drivers cannot turn right, but
cyclists can.
This junction works for now, but its days are already numbered. Work on re-opening the canal starts this year, and very soon this short stretch of road will be dug up and replaced by a modern bridge. What's more, cyclists in the future will be able to make left turns at this location, but that will still be possible without any conflict (see later updates).

Back in London, it is positive that TfL seems to be thinking about cyclists. We have to hope that their proposal of a redesign in the face of criticism is a sign that a positive change has taken place within the organisation. However, the proposal that they've put forward is inadequate.

People feel relaxed enough to cycle
through "no hands". Will this be true
at Bow roundabout in London ?
Where transport planning is concerned, London seems to be stuck 40 years in the past. This has to change, for the benefit of everyone.

It's been shown more than once that not only cyclists but also drivers benefit from the building of cycling infrastructure and higher rates of cycling. No-one in Britain benefits from the low quality of infrastructure being installed in the country.

Exactly the same problems arise in the Netherlands as in the UK, however the approaches taken to deal with them are very different. In the Netherlands, cyclists are not put into the firing line. Practices here are very much more advanced.

We run infrastructure Study Tours here in Assen and Groningen to demonstrate how the infrastructure in this part of the world works to keep cyclists safe and make cycling popular.

If anyone from Transport for London is interested in seeing a very different way of designing cycling infrastructure they might like to book a tour. Avoid confusion. Avoid wasting money and time on implementing second rate dangerous designs. Stop trying to re-invent the wheel.

Update July 2013
The junction in Assen featured in this blog post, a rare surviving relic of older design, is to be replaced and updated in the next few months.

Very sad update 13 November 2013
This junction in London was changed in the way that the city said it would and since that time it has claimed another life. There is a protest ride tonight (but note that London Cycling Campaign's suggested fix is very far from what is really needed). Before London can become a truly safe place to cycle it has to do a lot more than fix just one junction.

Please TfL, send someone. We can show you how to create proper safe cycling infrastructure which works for everyone.

Update July 2016
The old Assen junction featured in the video above has been completely rebuilt and it is now possible for cyclists to make a totally safe conflict free left turn across traffic at the new junction. Please read a new blog post which includes a description and video of the new junction design.

Read more posts about Advanced Stop Lines ( Bike Boxes ). Also note that one of the most important interventions with regard to traffic lights in the Netherlands is enabling cyclists to avoid them altogether.


Estudio27 Architects said...

Eloquently said, as always. To create subjective safety, remove conflicts - it's as simple as drawing coloured lines on a plan. Perhaps TfL could do with some new felt-tip pens?

christhebull said...

The original reaction was fairly positive, as the "early start" traffic lights at the end of the cycle lane sounded like they would have a short cycle only phase, similar to certain bus gates.

However, it was realised that all the cycle light would do is control access to the ASL by making it slightly safer to undertake other traffic to enter it (assuming traffic hasn't entered it illegally or is simply queuing across it due to congestion), with the head start being merely the time it would take for a driver waiting a few metres behind a cyclist to catch up with them. Meanwhile cyclists who use the cycle lane when traffic in the same direction is moving will get a red light, and it wouldn't surprise me if people either ignore the cycle lane completely, or jump the red light and risk getting left hooked.

It is worth pointing out that Paul James came up with an alternate turbo roundabout based on the premise that while most pedestrian and cycle movement is west to east, most motor traffic is turning left or right, because through traffic can take the underpass or flyover, with the exception of access to side roads in the immediate vicinity and buses which stop on the slip roads.

North to south cyclist movement is however insignificant - to the south the A12 goes through the Blackwall Tunnel where cyclists are prohibited, and cyclists are also prohibited to the north on the section of the road that is a former motorway (the only reason it was downgraded along with the A40 Westway was due to a legislative blunder that prevented TfL from managing motorways. It still looks the same, but doesn't have blue signs any more.)

Edas said...

David, nice to see you blogging again ;)

For anyone involved in city planning I highly recommend Hembrow's study tour.
Last autumn we took part in it and I'm really surprised to observe, that architects, who ride by bike to work, learned many things they didn't know before the tour.
It's obvious, that it is better one time to FEEL how things works than hundred times to read about that.

Koen said...

Hi David,
So basically your point is that with the shielded bike lane, advanced stop points and right traffic light timings, there is as little conflict as possible. I understand that the aim should be that for both drivers and cyclists there should be the least possible things to watch out for. Roundabouts are very busy to begin with, with al the signs,turns and other drivers, so drivers don't need people on bikes crossing unexpectedly. So yes, make the road so that everyone just behaves predictably. Mark has already pointed out in his excellent videos that the line of sight is so important, which corroborates with your video. Best practice would bee to have a separate cycle track some feet away from the roundabout, with the crossings several meters (1.5 carlengths) away from the roundabout, so drivers have room to stop for cyclists. But you know all that.
What you propose is very compact, and I have to say instead of a right turn (left on the Bow roundabout of course), your video shows an interval for traffic coming in from the left. Doesn't that change the way space is needed for the turn?