Traffic Lights vs Roundabouts at busy urban junctions

L1011 · 16-08-2011 01:59PM

monument wrote: »

Those two aren't comparable at all.

Yes, they are.

monument wrote: »

And the Dutch example is urban and nowhere near a motorway.

The Irish one just happened to be the nearest large, new roundabout to my house. There's many others.

monument wrote: »

Also -- very importantly -- the nearby network of side roads and cycle track in the Dutch example are by-directional on both sides of the roads around the roundabout. That's compared to fairly narrow, non-segregated one-directional footpath / cycle lane in the Irish example.

There isn't bi-directional on both sides cycle track *anywhere* in Ireland to the best of my knowledge. There appears to be some bi-directional single sided being put along the Grand Canal but thats about it.

monument wrote: »

Err... while that design likely isn't the highest of standards there, the inside line around the roundabout is a cycle track. The two side streets there also are 30km zones.

Doesn't look like it from aerial, it appears as a second lane due to not being of differently coloured asphalt as they usually are; on street view I'll concede that it is.

However there are plenty without cycle track, and the track there has no signed priority of any description. There's enough of that in Ireland too

monument wrote: »

I'm confused at how you think that the Irish and Dutch examples you compared, or in general, are anyway comparable examples.

They are comparable, and show that the delusion that there's some fanstastic magic cyclist-safe roundabout theres isn't true. Our current standards and their standards are virtually identical, with the exception of turbo's thankfully not being used here; and relying on the bulk of our roundabouts in urban areas being rather old or built by private enterprise with shoddy planning control makes for bad comparisons.

monument · 16-08-2011 02:17PM

MYOB wrote: »

Yes, they are.

No, as in general, the Irish example you used is nothing like the Dutch one. I've already outlined many of the reasons for this.

MYOB wrote: »

The Irish one just happened to be the nearest large, new roundabout to my house. There's many others.

It does not matter, the Dutch would not generally use that design anywhere. I'd be surprised if you could find more then one or two Dutch examples anywhere comparable to your Irish motorway example.

MYOB wrote: »

There isn't bi-directional on both sides cycle track *anywhere* in Ireland to the best of my knowledge. There appears to be some bi-directional single sided being put along the Grand Canal but thats about it.

Yes, one of the many reasons why your Irish example can't be compared to your Dutch example.

MYOB wrote: »

Doesn't look like it from aerial, it appears as a second lane due to not being of differently coloured asphalt as they usually are; on street view I'll concede that it is.

However there are plenty without cycle track, and the track there has no signed priority of any description. There's enough of that in Ireland too

Priority to pass is to those in the inside lane (in this case the cycle lane) and designs work differently when you have strict liability as they do in the Netherlands.

MYOB wrote: »

They are comparable, and show that the delusion that there's some fanstastic magic cyclist-safe roundabout theres isn't true. Our current standards and their standards are virtually identical, with the exception of turbo's thankfully not being used here; and relying on the bulk of our roundabouts in urban areas being rather old or built by private enterprise with shoddy planning control makes for bad comparisons.

Nope, even your newer Irish example is deeply flawed for cyclists by Dutch standards.

L1011 · 16-08-2011 02:27PM

monument wrote: »

No, as in general, the Irish example you used is nothing like the Dutch one. I've already outlined many of the reasons for this.

Its not "nothing like the Dutch one". Its a roundabout with a completely segregated cycle track which does not use the actual roundabout at all.

monument wrote: »

Yes, one of the many reasons why your Irish example can't be compared to your Dutch example.

Being non-comparable because we just do not do something in Ireland isn't the same as being non-comparable by being done differently.

monument wrote: »

Nope, even your newer Irish example is deeply flawed for cyclists by Dutch standards.

90 degree turns for cyclists makes it "deeply flawed" when they frequently do this for getting around other styles of junctions in NL? You really are nitpicking to try and desperately save your point here. Particularly as the point was originally safety and you're now trying to compare on speed of travel for cyclists...

Modern Irish larger roundabouts have segregated cycle tracks. Older ones don't. Dutch ones have segregated cycle tracks

Modern Irish smaller roundabouts have cycle lanes on them or ending at the yield line. Dutch ones have the same.

There is no magic roundabout style in NL that's safer for cyclists than what is being built here [when the state is building or has proper control over the building of the RAB. I'll concede that an arse has often be made of things by shopping centres etc putting roundabouts at their exits]

monument · 16-08-2011 02:51PM

It's not nitpicking -- details matter.

The detail in junction design and with things like segregation are the massively different here and in the Netherlands.

The city you used as an example is at 30% or higher modal share of cycling at least partly because of these details.

L1011 · 16-08-2011 03:03PM

the city in question is more compact, higher density and has virtually no parking. And one tram line.

monument · 16-08-2011 06:23PM

MYOB wrote: »

the city in question is more compact, higher density and has virtually no parking. And one tram line.

It also has a fairly advanced network of cycle tracks with far higher and different designs and standards on it, including at roundabouts.

Are you trying to make out that all Irish commuters have impossibly distances to travel by bicycle? To repeat myself from another thread: I'm not saying cycling is suitable for all journeys for everybody, but it is suitable for a lot of people's journeys. The 2006 census shows that that the average distances for travel were:

To work -- 15.8km;
Students 5-12 years old -- 4km;
Students 13-18 years old -- 7.6km
Students 19 and over -- 13km

Out of the total workforce of 1.8m (includes just under 400,000 who did not state a distance) a total of 908,121 said they travelled less than 14km -- distances which should be cyclable for most people. Of those 400,000 said they travelled between 1-4km -- an easy cycle. Source: Census 2006 --Volume 12, and the stats above were sourced from tables 05 and 26.

As for Utrecht -- As well as a "one" tram line with its branches which covers a good deal of the city, it also has a BRT line, other local and regional buses, a few train stations with local services, and a central train station served by international trains and a direct service to Schiphol Airport.

Also Dublin has higher density then Utrecht.

monument · 16-08-2011 06:35PM

Just to add to that, in Dublin City and County there were over 252,500 work commuters (excluding those who work from home) who commuted between 1-9km. And over 84,000 more travelled between 10-14km.

L1011 · 16-08-2011 06:44PM

monument wrote: »

Are you trying to make out that all Irish commuters have impossibly distances to travel by bicycle? .

Of course not. How on earth did you extract that from my post?

There are far less journeys that are cycleable in Dublin than in Utrecht

Utrecht's density figures hide the fact that Dublin has large low density areas with virtually no employment which generate a disproportionate amount of car traffic as a result. Utrecht is of a fairly consistant density for its entire area and doesn't have quite as high density a centre as Dublin. Seeing as its "city centre" consists of the old, rather low density city and the surreal "Hoog Catherine" shopping centre in the train station.

The tram line, last time I was there, had a branch, this may have changed. It served two outlying suburbs. The buses were surprisingly poor for NL, the taxis were cripplingly expensive (if fantastic cars, I was in a week old Insignia and a year old Merc S class for the two trips I took, with suited drivers...).

The trip from where I was staying to the city centre wasn't realistically walkable due to the way the road layouts were done without going through a very dodgy looking industrial area, it was cycleable along the main road in however due to segregated cycle-only paths.

monument · 16-08-2011 09:18PM

MYOB wrote: »

There are far less journeys that are cycleable in Dublin than in Utrecht

Maybe, maybe not, it's hard to know -- Utrecht can grow and Dublin is far even from reaching even the lower hanging fruit of cycling measures.

Dublin has huge potential. With the Greater Dublin Area, NTA use of the 2006 census shows that with the inner suburbs (ie inside the M50) over 80% of workers living within 10km of their workplace, and even the outer suburbs (broadly, around the M50) there's 57% of commuters who live within 10km of work.

BTW -- In the NTA and others now term as the city centre in planning terms (between the canals) has 88% of work commuters live between 1-10% of their work. In the hinterland towns (Navan, Balbriggan, Naas, Newbridge, Wicklow, and Arklow) it drops to just over 40%, and in the rural hinterland area (not just rural areas, see map in last link) it's a bit over 50%.

10km is by no means a max cycling distance (see some of the crazy distances some people commute on the cycling board - loads of old thread on it) but you'll start to get a sharp drop off of people around that figure even with upgraded cycle lanes. And, as before, cycling won't suit all of those people, but it can suit a lot more at the moment and even more if conditions are made better.

It all goes back to the topic at hand of how the small details change the experiences of road users. Cycling segregation Irish style has been a failure but with design Dutch and Danish differences, they have made segregation a success. Having to stop all the time and yield to side roads, slow to do small area 90 degree turns, and share "segregation" on for long distances on main routes with people walking, isn't the path to success.

And the potential goes further than just direct cycling commuting. In the Netherlands, for example, they estimate that at least 40% of train users cycle from their home to the train station.

galwaycyclist · 22-08-2011 09:57AM

MYOB wrote: »

Yes, they are.

They are comparable, and show that the delusion that there's some fanstastic magic cyclist-safe roundabout theres isn't true. Our current standards and their standards are virtually identical, with the exception of turbo's thankfully not being used here; and relying on the bulk of our roundabouts in urban areas being rather old or built by private enterprise with shoddy planning control makes for bad comparisons.

Apologies if this has already been dealt with but with respect I don't think this statement is strictly supportable. It's a bit like saying Irish men and Dutch women are identical because they both have arms and legs. It may be true that they both have arms and legs but there are other aspects of the design of both that mean we should not treat them as "identical".

There is a fair amount of literature on the differences between "continental" or Dutch style roundabout geometry and the UK/Irish roundabout geometry.

Dutch urban roundabouts tend to have smaller and "tighter" geometries with entries and exits that are perpendicular to the central island. UK/Irish designs tend to be larger and have entries and exits that are tangential to to the central island. As I understand it, a typical urban Dutch single lane roundabout would fit entirely within the central island of the typical UK/Irish equivalent.

To think of it another way, Dutch urban roundabouts tend to be set out as a series of t-junctions, UK/Irish roundabouts tend to be set out as a series of slip roads. The former design encourages entering traffic to slow and yield to other traffic in possession of the junction, the latter design encourages entering vehicles "to go for the gap" without slowing.

Since "failure to yield" by entering drivers is the biggest threat to circulating motorcyclists and cyclists, the Dutch version should be inherently safer than the UK/Irish version.

Iwannahurl · 22-08-2011 10:13AM

That's a very helpful plain English account of Irish versus Dutch/'Continental' roundabouts.

My experience of roundabouts in Ireland is that their design permits, perhaps even encourages, high speed entry and exit. Combine that with the lack of safe facilities for cyclists and pedestrians, and add the standard Irish driving practice of failing to indicate, and you have the ideal conditions for promoting fear and danger.

In my experience, the opposite is the case on Dutch roundabouts. Entry and exit speeds are lower, and cyclists and pedestrians are normally prioritised in any case. Plus cyclists have legal protection and socio-cultural status that far exceeds that in Ireland.

The Celbridge example above is not comparable to the Dutch situation, except in a few superficial details.

Traffic Lights vs Roundabouts at busy urban junctions

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