CTC capitulation?

[summerdays]

I don't know the area, so I don't know the types of cyclists that would even try to use that area. I think the concept of prioritising the safety of existing cyclists is sensible. Build the routes for aspirational cyclists in nice places, that hopefully link up with residential bits or car parks where they take their bike to by car. (That is how I started ... the once a year trip to the Forest of Dean, but it would be madness to waste limited resources on that once a year person). The places that I would like to see prioritized for cycle paths would be routes to school, so that we can encourage the next generation (and particularly their parents), onto bikes.

 

[jonesy]

The world does not divide neatly into existing cyclists who are all confident vehicular cyclists and potential cyclists who all want segregation. You don't see supermarkets treating existing customers as a completely different market from potential new ones, or thinking that providing a good service for existing customers has nothing to do with attracting new ones.

 

[Flying Dodo]

That is clearly all true, but he has still designed a roundabout whose first goal is to increase motorised traffic capacity, and happily ignored the needs of "not yet cyclists", which hardly makes him a reasonable hero figure for cyclists.

"Not yet cyclists" aren't ignored, as they will be using the widened zebra crossings to be installed on all arms. As mentioned previously, there isn't space to put in a fully segregated solution such as a proper Dutch style roundabout.

 

[GrumpyGregry]

The world does not divide neatly into existing cyclists who are all confident vehicular cyclists and potential cyclists who all want segregation. You don't see supermarkets treating existing customers as a completely different market from potential new ones, or thinking that providing a good service for existing customers has nothing to do with attracting new ones.

Explain that to Sustrans.

 

[stowie]

I notice in this article from road.cc that the lane widths will allow a car to overtake a cycle on the roundabout if the cyclist is near the divider, but a lorry won't be able to get past without moving lane. Sounds like a recipe for close passing of cyclists to the left of the lane and harassment of cyclists taking primary. If they are going to do this then they need to make the lanes narrow enough to stop cars overtaking, but I guess this would then mean a lorry wouldn't be able to negotiate the roundabout in lane.

If the lanes don't slow down cars to 10-15mph around the roundabout this scheme sounds really poor. I have driven around the roundabout in question a number of times and the cars tend to attack it at pretty high speed and drift from lane to lane. To get a slow down to 10-15mph will involve some serious tightening of the roundabout lanes.

 

[Flying Dodo]

And then you'll have all the drivers whinging about cyclists' using zebra crossings if they cycle over... as, of course, cyclists are not allowed to cycle across Zebra, Pelican or Puffin crossings.

Exactly. And unfortunately.

 

[stowie]

"Not yet cyclists" aren't ignored, as they will be using the widened zebra crossings to be installed on all arms. As mentioned previously, there isn't space to put in a fully segregated solution such as a proper Dutch style roundabout.

There is space, but not without taking out a motor lane and reducing roundabout capacity.

The decision to not implement a dutch style roundabout is a political one which places the need for traffic throughput above the need for cycle infrastructure. It is not a case that there is physically not enough room on the roadway to build the infrastructure. Who knows, maybe that decision is the correct one for this junction. What is known is that the changes are going to be funded by the cyclist safety fund (Bedford council state this on their documentation, although they don't say how much the works will cost).

We have had decades of road planning where all consideration was given to movement of motor traffic. DfT rules on road planning all reflect this mentality. I understand the changing of this will also take decades. But I still think not backing this plan is a valid option. Money hopefully would stay in the safety pot for another scheme, one where the improvement to safety may be more than this scheme.

 

[Pete Owens]

No, this is a scheme that very much prioritises cycling by reducing the motor traffic to cyclist speed. Now of course, a single lane compact roundabout would be preferable if the traffic volumes were low enough, but the design still very much incorporates the essential features that make Dutch roundabouts so much safer than ours by keeping speed low - perpendicular entrances and exits, tight constrained circulating lanes and single lane exits. And it is not just theory or speculation but empirical study of a large number of such conversions in the NL that showed a large improvement in safety as a result of the significant reduction in speeds (and that safety improvement was for existing Dutch roundabouts that already had a good safety record compared to ours).

As one who has actively campaigned (without success due the fierce resistance of highway engineers who are segregationist to a man) for this sort of thing for years it seems absurd to suggest that this represents a "capitulation" to them. If that was the case there would be thousands of these things installed in the UK rather than this being the first case.

It is not a matter of maximising throughput (which this will certainly not do) but of designing a junction that will massively improve conditions for cyclists while still maintaining the ability to carry the current volume of motor traffic. To argue for your personal favourite form of infrastructure irrespective of the impact on other road users is not going to get you very far. Even if you were to persuade them to install a junction with lower capacity than the current usage the subsequent gridlock would generate a massive political backlash that would ensure the junction was restored to its former state within a matter of weeks.

 

[totallyfixed]

I do wish we would stop calling this a "Dutch" style roundabout, it is not. I have ridden around plenty in the Netherlands and this is not anything like them. The few "turbo" roundabouts that exist in the Netherlands are actually designed to get motorised traffic moving quicker! Please read this before commenting further.
http://bicycledutch.wordpress.com/2013/05/09/a-modern-amsterdam-roundabout/

 

[Pete Owens]

For fans or orbital cycle paths it is worth taking a look at the BBC video of the one being tested by the TRL.
http://www.bbc.co.uk/news/uk-england-london-22347184
Remember this is in an idealised and controlled setting, with no distractions or pedestrians and low volumes of traffic. The drivers know that they are being observed so they are on their best behaviour and they know that they are testing out cycle infrastructure so they know to be expecting cyclists - who are all travelling at a modest pace. Yet in just a short visit by the camera crew they managed to spot see a near crash. Scroll the video to 2 minutes - it is a good job she was covering the brakes.

Again the basic geometry of the roundabout is good, with the single lane perpendicular approaches and exits and tight circulating lane. It would be a huge safety benefit for cyclists riding on the carriageway, but unfortunately I think the results of the trial will end up prohibiting the use of this geometry due to the only monitoring cyclists riding on the dangerous orbital path.

It is also worth noting that the Dutch road safety institute (SWOV) recommends that priority should NOT be given to cycle tracks orbiting roundabouts for safety reasons - See page 4:
http://www.swov.nl/rapport/Factsheets/UK/FS_Roundabouts.pdf
where it says:

Fortuijn (2005b) concludes that the number of injury crashes on roundabouts with priority for cyclists was more than twice the number on roundabouts where they have no priority

 

[Pete Owens]

I do wish we would stop calling this a "Dutch" style roundabout, it is not. I have ridden around plenty in the Netherlands and this is not anything like them. The few "turbo" roundabouts that exist in the Netherlands are actually designed to get motorised traffic moving quicker!

I use "Dutch" in the conventional sense of the word meaning "something originating from the Netherlands" - rather than the way some segregationist campaigners use it to mean "Something I personally approve of". Turbo roundabouts were introduced to improve the safety of multi-lane roundabouts - which they did with dramatic effect. Now since Dutch multi-lane roundabouts were already designed with safety in mind (rather than speed and capacity as in the UK) they were pretty inefficient so the turbo design does improve the capacity (not speed) as well as a side effect.

They are used in compact urban situations (and this is what the Bedford design is modelled on) as well as the larger rural high speed major road junctions referred to in that link.

 

[jonesy]

User, you could start by reading the TAL on continental geometry roundabouts I posted previously.


Ps- and if you are going to start demanding links off people, then one to support your theories as to why Dutch roundabouts are safer would be helpful...

 

[stowie]

For fans or orbital cycle paths it is worth taking a look at the BBC video of the one being tested by the TRL.
http://www.bbc.co.uk/news/uk-england-london-22347184
Remember this is in an idealised and controlled setting, with no distractions or pedestrians and low volumes of traffic. The drivers know that they are being observed so they are on their best behaviour and they know that they are testing out cycle infrastructure so they know to be expecting cyclists - who are all travelling at a modest pace. Yet in just a short visit by the camera crew they managed to spot see a near crash. Scroll the video to 2 minutes - it is a good job she was covering the brakes.

Again the basic geometry of the roundabout is good, with the single lane perpendicular approaches and exits and tight circulating lane. It would be a huge safety benefit for cyclists riding on the carriageway, but unfortunately I think the results of the trial will end up prohibiting the use of this geometry due to the only monitoring cyclists riding on the dangerous orbital path.

It is also worth noting that the Dutch road safety institute (SWOV) recommends that priority should NOT be given to cycle tracks orbiting roundabouts for safety reasons - See page 4:
http://www.swov.nl/rapport/Factsheets/UK/FS_Roundabouts.pdf
where it says:

What are the safety statistics between having a dutch style roundabout with off-road tracks (prioritised or otherwise) and the scheme proposed in Bedford where cyclists go around with the traffic flow?

Why do you think the NL has (without exception?) implemented turbo roundabout with separate provision? Is this more ideology than based on data?

I do hope the turbo roundabout has the desired effect for cyclists, not least because it would be easier to implement this elsewhere. But I cannot see some basic questions not being answered

The safety aspect, if cyclists are to be made safer whilst riding in the traffic flow relies very heavily on two conditions

1) Traffic flow is reduced - by roundabout design - to 10-15mph, so all traffic is travelling at around the same speed. I see expectation of this happening, but does anyone have data on entry / exit speeds for traffic on existing turbo roundabouts with approximately the same dimensions? I have driven this roundabout in the past and entry / exit speeds by drivers can be in excess of 30mph - it is actually a horrible roundabout for drivers as well because of inappropriate speeds. A reduction to 10-15mph seems ambitious especially without understanding the traffic speeds that can normally be expected on turbo roundabouts.

2) Close passing, left hooks are eliminated by forcing traffic to hold a lane and preventing traffic from being able to overtake cyclists on the roundabout whilst in the same lane. From some of the diagrams it seems that cars will be able to overtake cyclists on the roundabout if the cyclist isn't in primary, and the lane delineations can be crossed by drivers as well.

If the design allows speeds significantly in excess of cyclist speeds, and also doesn't prevent overtaking on the roundabout I have deep concerns over how this will improve matters for cyclists.

I assume that existing designers of turbo roundabouts in places like the NL have been consulted - what do they think to the scheme?

 

[benb]

I do wish people would stop presenting this as a Dutch cycle-friendly roundabout, when it's nothing of the sort.
In NL, when they use turbo roundabouts like this, they always, always have separate cycle provision rather than expecting the cyclists to mix with motorised traffic on the roundabout.

This is motoring infrastructure, not cycling infrastructure, and to pretend otherwise is deeply disingenuous.
The fact that it was paid for out of a cycling safety fund is scandalous.

 

[jonesy]

Benb- I feel this is getting repetitive, but again, if this were being designed primarily as motoring infrastructure it would have a completely different design, wider lanes, longer turning radii. The whole point is to reduce traffic speeds, reduce passing and improve sightlines. This is a different application of continental geometry, which is safer for cyclists both with and without segregated lanes. How effective this particular design will be remains to be seen, that's the whole point of doing trials. Please can we stop this assumption that we know what the outcome will be, based on outrage from bloggers for whom segregation is the one and only truth!

Stowie- as before, I understand your concerns, some of which I share. Let's see what the outcome of the trial is. But please don't assume your experience of speeds on the current layout is a good predictor, as, if it is being redesigned as described (I've not seen detailed drawings) then the geometry will be very different.

Picking up some of your questions:
The Dutch use far more segregation anyway, so it isn't surprising they would more usually use the turbo design with segregation. But that doesn't mean it can't deliver benefits for unsegregated cyclists. It is very useful to explore what can be done in a UK context. That means trials and we can't assume that Dutch experience can simply be transferred. Regarding comparative data, there isn't actually that much available. Pete Owens has posted the only comparison that I've come across yet- and note the concerns about priority orbital lanes. Note also that there are difficulties comparing like with like because I don't think they've fully accounted for exposure. Clearly you can't expect there to be good comparative data available for the Bedford proposals and other Dutch roundabout designs if it is being used in a different way anyway. That's why we need trials!