LCDS Junction audits

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20 January, 2015 - 11:24
#1
As Easy As Ridi...
LCDS Junction audits

I thought I'd start a thread for people to post their audits of junctions, using the London Cycling Design Standards Junction Assessment Tool.

It can be found in Chapter 2 of LCDS - 'Tools and Techniques', but I've posted it here for reference.

LCDS Junction Assessment Tool

Each potential movement at a junction is scored as follows - 

  • ​not allowed/red = 0
  • amber = 1
  • green = 2

For a crossroads, there are 12 potential movements (left, right, straight-on, on each arm), so the total potential score is 24. 

For a t-junction, there are 6 potential movements (2 on each of the three arms), so the total potential score is 12.

Each movement is rated according to the suggested criteria in the table above. You can post your assessment - with diagrams if you like! - in the thread below. 

Submitted by As Easy As Riding A Bike on 20 January, 2015 - 11:24
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20 January, 2015 - 11:28
As Easy As Ridi...

To get the ball rolling, here's an assessment I've made of a junction (possibly the worst junction) in the centre of Horsham - the junction of Albion Way (the inner ring road) and Springfield Road.

Albion Way/Springfield Road LCDS

It scores 5/24 - which is pretty abysmal, but much to be expected. You can see why by exploring the junction on Streetview.

Submitted by As Easy As Riding A Bike on 20 January, 2015 - 11:28

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20 January, 2015 - 14:18
(Reply to #2)
DurhamBUG

(edited: first response was blank)

Interesting stuff.

I'd like to know a little more about your assessment method.

Looking at the table, I'd be tempted to put route 7 as Green, with the ban on vehicles turning into that road and a 'physically protected' turning for cyclists. But I can see the volume and speed of traffic going straight on would detract from that & it could be Red.

So how did you balance them and come up with Amber?

Submitted by DurhamBUG on 20 January, 2015 - 14:18
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20 January, 2015 - 15:42
(Reply to #3)
As Easy As Ridi...

My reasoning for awarding turn 7 an amber are that there is no clear near-side access (i.e., no way to access the turn when signals are red); there are multiple lanes; and traffic speeds are high. So pretty much what you said! 

I also find that it's hard to make this turn safely, because it is quite a tight corner, meaning you have to slow a great deal, which is not particularly comfortable given the traffic speeds here. 

So on balance - although the turn is protected - I thought an amber rating was a fair assessment.

Submitted by As Easy As Riding A Bike on 20 January, 2015 - 15:42

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21 January, 2015 - 00:46
(Reply to #4)
pete owens

Just considering the junction as opposed to the links:

Since there is no motor traffic allowed to turn across the path of a cyclist at that junction (ie both the first two measures listed in the green category) I would categorise both 7 & 8 as green. I would also put 10 in that category as a left turn from the quietest arm. (I'm not saying that Albion Way is an ideal link to cycle along, just that the junction poses no particular issues for those movements over and above what you would encounter riding along the road).

I would put 1 in amber (4 is probably worse with that nasty sub-standard cycle lane) though the guard railing might justify red. 2 is red due to the large radius - thus high speed turning across the path of cyclists.

5 & 6 are justifiably red, mainly due to the left hand filter lane - particularly as the narrow cycle lane funnels cyclists off to the right. 9 is obviously red.

12 would depend on the phasing of the lights.  If both the north and south arms have simulaneous green lights  then that would be a difficult manoevre. However, if north bound traffic has its own stage then that would be amber (though if the all-red time was too short there is the potential to conflict with opposing traffic turning left.

All this does not make the junction any less bad, it is just a more discriminating use of the scale. There is a huge difference between movements 8 & 9 through that junction.

 

 

 

 

 

 

Submitted by pete owens on 21 January, 2015 - 00:46
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31 January, 2015 - 15:06
(Reply to #5)
As Easy As Ridi...

Hi Pete,

I don't think you are using the LCDS tool correctly. A 'red' rating is awarded if any of the factors in that column are present. 

So - for instance - movement 8 is an obvious red because of cycling on multiple lanes, high speed traffic, and no clear near-side access. The scorings are not arbitrary. 

 

Submitted by As Easy As Riding A Bike on 31 January, 2015 - 15:06

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1 February, 2015 - 02:34
pete owens

In which case the tool would be next to useless.

If it cannot discriminate between movement 8 - which is one of the least problematical movements though the junction, with no turning conflicts whatsoever - and movement 9 which involves filtering into lane 3 of a dual carriageway then it really tells you nothing useful about the difficulties cyclists face at junctions.

If approaching a junction up-hill is always going to give a score of zero, then there will be no point in mitigatating any of the other features that cyclists might face. This would be perverse as an uphill approach makes it more important to treat the other factors.

If a road has multiple lanes that is only an issue for those movements that need to cross them. A left slip lane is not an issue if you are turning left and so on.

However, what the document actually says is: 

In order to help assess junction movements, figure 2.4 suggests typical scenarios that might lead to a ‘red’, ‘amber’ or ‘green’ rating.

ie it is a matter of judgement how much any of those factors would contribute to the assesment.

In this particular example - what any audit should highlight is the undue difficulty of proceding straight on crossing the dual carriageway from N-S - movement 5 (which I guess is the most important route for cyclists being a radial route to the town centre). This could be mitigated by removing that triangular island and making the junction at right-angles with tight radius curves - I doubt there is much left turning traffic taking advantage of that filter lane in any case. Ensuring that N bound and S bound traffic have separate stages at the lights would further improve the situation. 

 

 

Submitted by pete owens on 1 February, 2015 - 02:34
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9 February, 2015 - 21:49
(Reply to #7)
As Easy As Ridi...

The tool doesn't need to 'discriminate' if both movements fall below an acceptable standard. The purpose of the tool is to highlight flaws, not to provide some kind of subjective grading of the junction from bad to worse. 

If one movement is slightly less awful than the other, that doesn't need to merit a separate category for both. Movement 8 has two indicators in the red category; that's enough. It shouldn't be graded higher just because Movement 9 is even worse.

Submitted by As Easy As Riding A Bike on 9 February, 2015 - 21:49

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