North Tyne Coastal Bike Grid

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tombaileytyne
North Tyne Coastal Bike Grid

I thought I’d have a go at using this section of the forum for a bit of collaboration on some infrastructure we are looking to see built. Background info at:

http://www.tynebicycle.co.uk/blog/building-a-coastal-bike-grid

tombaileytyne
map

Jim
This looks very interesting

[I’m going to ask you a really stupid question now but] have you seen the following..

http://hembrow.blogspot.com/2011/05/priority-for-cyclists-on-roundabouts...

or this..

http://hembrow.blogspot.com/2008/10/roundabouts.html

or indeed our wiki entry

http://www.cycling-embassy.org.uk/node/226

Are you suggesting some form of physical seperation for cyclists from motorists or is it going to be a mandatory lane without priority?

tombaileytyne
Jim, seen some or most of

Jim, seen some or most of that. The roundabout design I’ve been working on with on road lanes is cribbed from one shown on the Hembrow blog. What would be needed would be physical separation either using a kerb or planters as far as is possible (buses need to get through).

tombaileytyne
roundabout

This is a design for a roudabout on the route, context is that its the gateway to a 20mph zone, currently has two pedestrian crossings. I’m suggesting that this is increased to four (shown orange) and the outerlane of the roundabout is converted to bike lane (shown green).

tombaileytyne
general principles

to try and prevent latter butchering of scheme by highway engineers it seems to me that we should try and get something like this agreed, needs some work:

1/ deliver a continuous high quality route from NS to WB with branches to Cullercoast and Tynemouth of a standard that is equally practical and attractive to:
a) an adult commuting cyclist needing to average 20 mph
b) a school run mum with two young kids averaging 5 mph
c) a mobility cart user

2/ Cede priority at no more than 4 points over the route i.e. priority over all minor roads.

3/ consider:
a) 2 way cycle tracks as per Camden Tavistock Place
b) bicycle roads
c) 2 metre wide on road cycle lanes ; where carriageway not wide enough then remove centre line and allow motor traffic to encroach, otherwise mandatory
d) Hybrid lanes
e) Dutch Standard bikeways on each side of carriageway

4/ Dutch Roundabouts, both smaller style with on road lanes and larger traditional segregated lanes.

5/ Shared space – only where traffic volume is below 100 vehicles per hour, otherwise separation required

6/ Town Centre pedestrianisation

7/ Pair cycleways with pedestrian crossings at junctions

8/ Publicly commit to keeping routes open 12 months of the year, if neccesary using commercial sponsorship to achieve this.

pete owens
Placing on road cycle lanes

Placing on road cycle lanes round the perimiter of a roundabout (or at least a roundabout of UK geometry) is a very very bad idea. It was trialled by TRL at a few locations several years ago. The early results were so dramatic that they abandonned the trial and painted out the lanes in the interst of safety.

I witnessed such a sheme in action after a CTC conference in Liverpool when the cycling officer took us on a tour of their facilities. While she was addressing most of us a few brave individual were trying out the lane, and there ware frequent near misses - in quiet Sunday morning traffic. We asked her to turn round and look at  her handiwork in action. That scheme has aloso been removed. 

The reason is that on roundabouts people use road position to signal and to judge direction of travel. If you ride around the edge whether or not in a cycle lane) you are effectively signalling an intention to leave at the first exit - thus other drivers will overtake and turn left across your path or enter the roundabout inm front of you.

The difference between UK and Dutch roundabouts has absolutely nothing to do with cycle facilities (which tend to be common to both UK & NL design) and everything to do with the basic geometry of the roundabout.

UK roundabouts are designed to optimise the speed and throughput of motor traffic. They have wide circulating carriageways, multi-lane approach arms and tangential entries and exits allowing motor vehicle to pass through the junction at speed. This is why they are so dangerous for pedestians and cyclists (whether on the carriageway or segregated paths crossing the entries and exits) .

Dutch roundabouts are designed to calm traffic. There tends to be a single circulating lane and the approches are narrower and perpendicular to the roundabout. Drivers have to slow down make a concious right turn onto the roundabout drive round the fairly tight geometry and then make another concious right turn to leave it, rather than swoop past a slight deviation.

Compare these 2 examples - one from Assen and one from Warrington:

http://maps.google.co.uk/maps?q=assen&ll=53.011659,6.554275&spn=0.000645...

http://www.google.nl/maps?q=warrington&hl=nl&ll=53.401143,-2.624654&spn=...

They are both at the same scale. In both cases cyclists are provided with cycle paths. In both cases the cycle paths give way at the junctions. Yet you can tell at a glance which is which. 

 

 

sallyhinch
I think this is a good point

It's both geometry AND cycle lanes, although sometimes people come away with the idea that all we need is to copy the tight geometry and still leave bikes with the problem of having to circulate on the carriageway with the cars (which we never had to do when we visited Assen) which is stressful for all concerned. Pretty much all of the times in the UK when I've thought I was going to get killed have been on roundabouts and they're a huge barrier for cyclists if there's no alternative to a big multi-lane roundabout

Lots on Dutch roundabouts here http://www.fietsberaad.nl/index.cfm?lang=en&section=Voorbeeldenbank&mode=list&ontwerpvoorbeeldPage=Rotondes for those interested, including the turbo roundabouts, which handle multi-lane roundabouts without the need for lots of lane switching by drivers

AKA TownMouse

pete owens
I did think that putting

I did think that putting cycle lanes on roundabout was always a very bad idea. But if you do it like this it encourages cyclists to adopt a good road position:

http://www.fietsberaad.nl/index.cfm?lang=en&section=Voorbeeldenbank&mode=detail&repository=Bicycle+roundabout+prevents+blind+spots

The dimensions (see slide 3) are critical. The cycle lane MUST be at leat 2m wide (which is true for all cycle lanes) and the space either side MUST be narrower than a car to prevent overtaking or undertaking. Unfortunately, the design would almost certainly fail a safety audit in the UK.

Dr C.
Dr C.'s picture
Changing the geometry without

Changing the geometry without adding the lanes is about as helpful as adding the lanes without changing the geometry. It is important to adopt the whole package rather than go down the route of Dutch Pick & Mix

pete owens
UK roundabouts are dangerous

UK roundabouts are dangerous only because their geometry encourages turning at speed. They are dangerous for cyclists riding on the carriageway and they are even more dangerous for pedestrians (who are universally segregated in the UK and NL) crossing the entry and exit arms. Putting cycle lanes or paths round the circumference of roundabouts makes the even more dangerous because you are approaching the junction from a direction where drivers are not expecting other traffic.

Continental roundabout geometry is very much safer, both for cyclists and pedestrians  because you are slowing down the traffic to cycling speed. Indeed, for right turning cyclists they are preferable to traffic lights as you dont have to filter across a lane of traffic. However, it is still the case that cyclists are safer riding on the carriageway than on separate cycle paths - it is just that the junction is so very much safer inherently that a cyclepath  is at all workable.

So changing the geometry (ie what the Dutch do - with or without a cyclepath) does make sense - while installing a cycle-path without changing the geometry (what we do in the UK)  is homicadal. 

By the way here is an example of a Dutch roundabout without cycle lanes:

http://g.co/maps/ecpzw

It it pretty similar in size and function to a one where I saw an example of a lethal preipheral cycle lane in Liverpool.

sallyhinch
There's some research here

On the research wiki page there's a paper on the safety of Roundabouts from 2005  (“Traffic Safety Effects of Roundabouts: A review with emphasis on Bicyclist’s Safety”) which is available as a download http://www.ictct.org/dlObject.php?document_nr=25&/S3_Daniels.pdf - From the summary, it does look as if on the whole separated lanes are safer than mixing with traffic for bikes, but maybe someone with more academic expertise than I can have a look at it to see if it's sound.  I may be biased, because I loathe cycling round roundabouts and far prefer the Dutch-style ones with the separate tracks.

AKA TownMouse

sallyhinch
PS your example intrigued me

so I dug out David Hembrow's blog piece Every Roundabout in Assen http://hembrow.blogspot.com/2011/09/every-roundabout-in-assen.html

It looks like that's the only one in the town that doesn't have segregated lanes  and all the roads are 30 km/h ones - equivalent of a mini-roundabout in a UK town. Those I don't mind!

AKA TownMouse

pete owens
If you look at the two

If you look at the two examples above  of roundabouts where I explaned why it is the geometry of Dutch roundabouts that make them much safer you will see that the one of the examples is indeed one of those in Assen, this illustrates all the features the design geometry which I am advocating - as do all the others on Hembrow's blog. That is because Dutch engineers understand the importance of controlling traffic speeds.

The other one is in Warrington where I live - it has cycle paths because UK engineers think that the only thing that matters is segregation. I could post endless other similar examples - roundabouts are very popular in Warrington as are segregated cycle paths. The roundabout geometry is designed to maximise traffic speed and throughput . It is perfectly possible for drivers to negotiate the roundabout at 40mph.

I too find riding round UK geometry roundabouts unpleasant and intimidating - but I also find attempting to cross the muliple lanes of fast moving traffic on the entry and exit slip roads to get from one stretch of cycle path to the next even more  intimidating. I want to improve the situation by getting UK engineers to adopt continental design. I don't think I would have an issue riding on those paths in Assen, but then those roundabouts would not be in the least bit intimidating to ride on the carriageway since they are designed to slow the traffic down to cyclist pace.

Now I took a look at the paper you linked and it does refer to geometric feaures:

EFFECTS OF DESIGN ELEMENTS

Generally, smaller and one-lane-roundabouts seem to be safer for bicyclists then larger ormulti-lane roundabouts (Brüde en Larsson, 1996). Since smaller roundabouts seem to besafer than large ones, the opposite is true for the dimension of the central island.Roundabouts with a central island of more than 10 meter are safer for bicyclists thanroundabouts with smaller central islands (Brüde en Larsson, 2000).
These are some of the basic features I am advocating - a small overall diameter with a large central island.The other important feature is the perpendicular approach lanes - but that seems to be common to all Dutch roundabouts. With regard to national characteristics, this section is interesting: 
EFFECTS ON ACCIDENTSRoundabouts seem to induce a higher level of bicyclist-involved accidents than could beexpected regarding the presence of bicycles in total traffic. In Great-Britain bicyclist’sinvolvement in accidents on roundabouts was found to be 10 till 15 times higher than the involvement of car occupants, taken into account the exposure rates.Nevertheless, roundabouts appear to have made traffic situation safer, also for bicyclists.However, opposite to the major results that were noticed for traffic on roundabouts in general (see before) the results for bicyclists were at a considerably lower level. Schoon enVan Minnen (1993) studied safety records of 185 roundabouts and reported a bicyclist’straffic victims reduction of 30% compared to the period before construction of theroundabout, while overall traffic victims decreased with 95% (car occupants), motorcycles(63%), pedestrians (63%) and other road users (64%). 
 OK the translation seems to be a bit iffy, but the message I get from this is that evidence that roundabouts are dangerous comes from the UK (unsurprising to those of us here), but they don't seem to look into any detail about why the UK should be so out of line. With regard to facilities:
TYPE OF CYCLE FACILITIESSchoon en Van Minnen (1993) investigated also the number of bicycle accidents related tothe type of cycle facilities on roundabouts: no particular cycle facilities, an adjacent cyclelane on the roundabout and a separated cycle lane. They concluded that differences in theaccident frequency between the several types were small. However, regarding to injuries instead of accidents they concluded that separated cycle lanes (situations 3 and 4)performed better than both the mixed traffic (situation 1) and adjacent lane (situation 2)alternatives.
  When traffic researchers report that the effects of cycle facilities are small it usually is a sign that the effect is adverse - especially if they then look for a secondary statistic. Data for accidents tends to be fare more robust than for injuries as there is so much more data. Incidently this is why the most reliable research tends to look for conflicts (ie observing near misses) as you can collect much more data. But basically from that paper I get the messages:
  1. that Dutch Roundabouts perform much better than UK ones.
  2. that the geometrical features are important for cyclist safety.
  3. that (at least for safe Dutch roundabouts) cycle facilities do not make much difference.
  
Dr C.
Dr C.'s picture
 that Dutch Roundabouts

 

  1. that Dutch Roundabouts perform much better than UK ones.
  2. that the geometrical features are important for cyclist safety.
  3. that (at least for safe Dutch roundabouts) cycle facilities do not make much difference

I agree that the cycle infrastructure component on Dutch roundabouts may not make an important contribution to objective safety. I feel that everyone else here is in agreement that Dutch geometry is integral to fixing our roundabouts, but why not do exactly what they do, including the cycle infrastructure component, rather than picking bits and pieces of what they do and hoping is still works? The cycle path on the roundabout is the subjective safety component, the geometry gives most of the objective safety.

What's wrong with addressing both types of safety when fixing British roundabouts?

As Easy As Ridi...
Which roundabout in Liverpool

Which roundabout in Liverpool was that? The only reason I ask is that the roundabout you have shown in Assen is in a residential area, with no through traffic.  

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