[TCUG] Re: Advanced stoplines for cyclists ASL's
- From: "Harrison David" <david.harrison@xxxxxxxxxxxxxxxx>
- To: tcug@xxxxxxxxxxxxx
- Date: 25 Jun 2004 11:44:00 -0000
Rob
We went through this in some detail 19/09/03, and I copy/paste at the foot =
of
this current sheet the exchange at the time. As far as I am aware, the appr=
oach
length as Andrew says is still largely determined as set out in TAL 8/93. W=
here
there are any doubts, I demand Linsig data on queue lengths when carrying o=
ut
Safety Audit on ASLs.
The Newcastle Cycle Forum accepts that sometimes we "omit" for good reason =
an
ASL and its approach where safety is "reasonably" considered to in conflict
with dogma.
There is also some good general reading in the new Chapter 5 of the Traffic
Signs Manual in sections 16.1 to 16.25. Section 16.13 also refers to current
on-line debate on that issue
Thanks
David Harrison
Newcastle City Council
Andrew Boyle (25/06/2004 09:37):
>Rob,
>
>If you delve into your old Traffic Advisory Leaflets, number 8/93 included=
a
>statement;
>
>"The length of cycle lane on the approach will vary according to the
>particular cicumstances of individual sites but should generally be as long
>as the longest queue of traffic when the signal is red."
>
>Maybe this is the article you are trying to remember?
>
>Regards
>A R Boyle
>Traffic Signals Unit
>Somerset.
>
>-----Original Message-----
>From: R.J.Perry@xxxxxxxxxxxxxxx [mailto:R.J.Perry@xxxxxxxxxxxxxxx]
>Sent: 25 June 2004 10:17
>To: tcug@xxxxxxxxxxxxx
>Subject: [TCUG] Advanced stoplines for cyclists ASL's
>
>
>Ladies and Gentlemen can you provide some advice please.
>I have been scratching my head trying to remember where I read about the
>length of near side cycle-lanes leading to ASL.
>
>The only other information I recall is that the article or advice said
>that ASL's with no cycle lane or a very short lane were pointless as the
>cyclist couldn't get to the ASL.
>
>Can anyone remind me where I may have read about this.
>
>Many thanks
>
>Rob
>
Copy/paste by DH of 19/09/03 contribution:-
Bruce
I was simply advocating some caution. I placed my first ASL some 30 years a=
go
at Barrack Road A189/ Hunters Road as a then experimental idea, as a safety
scheme with old 75% grant system and we achieved a very good reduction in t=
he
number and severity of cycle accidents. At the time, the concern was the
"sqeeze" on the approaches, and we simply sacrificed a bit of capacity by
reducing the number of approach lanes to get a good lead-in to avoid migrat=
ing
the accidents upstream of the then problem area. As you advocate, where it =
is
all a bit tight, we get in a shorter approach to comply with the 2002 TSR&G=
D.
That change in the detail perhaps reflects the potential difficulties.
We now have many ASL's. Vunerable users are very important and in Newcastle=
on
the key indicator of Child KSI, we have already achieved a 49% reduction
towards the 2010 target of 50%.ASL's are a good idea, but we need to be jus=
t a
little careful in using them as a universal panacea at every site.
Like you, we use colour contrast, and we have just completed a review of PS=
V.
Some of our earlier schemes had used a differential value, and a car under
heavy braking on the approach section with two wheels on the then higher PSV
(with "tight" lane widths) could skid unpredictably to the left and endange=
r a
cyclist about to be overtaken.
In the end it is a balance of helping the minority vunerable users in every=
way
we can, but checking that the accident reduction targets are reviewed,
particularly at the more difficult sites. I endorse the issue you raised on
pedestrians particularly from the point of view of intervisiblity.
Thanks
DH
Bruce Slattery (19/09/2003 16:43):
>I am sorry but as an engineer who cycles I would have to say that chance =
=3D
>is an every day part of cycling in a big city, ASL's do at least highlight=
=3D
>that cyclists are there and allow the cyclist to get in front of the cars =
=3D
>thus to command a better position when setting off through the junction.
>
>When you review the accident history and assess the numbers of cyclists =3D
>being injured (many severely) surely it is part of our job (and duty of =3D
>care) to do the best for these particularly vulnerable users of our =3D
>highway.
>
>As a major City we have a policy of putting ASL's in unless it is not =3D
>reasonably practicable, this tends to mean not on the circulatory arms of =
=3D
>signalled roundabouts and at isolated pedestrian crossings. All other =3D
>approaches can generally have ASL's fitted in some form or other if you =3D
>try hard enough. We have been doing this for several years now and have =3D
>not seen a noticeable increase in accidents due to these facilities.
>
>Another development is that we have a lot of support for ASL's from =3D
>pedestrians as it makes the vehicle stopline further from the crossing =3D
>point thus improving the pedestrian environment. we also now routinely =3D
>colour the ASL's red as this helps enforcement.
>
>We also can usually get some sort of approach lane in even if somewhat =3D
>short which seems to be accepted by cyclists and again does not cause a =3D
>safety problem.
>
>I would be interested to know if any other authorities have actually =3D
>caused an accident problem in these cases as this might support (or =3D
>otherwise) the safety audit recommendations and provide hard not anecdotal=
=3D
>evidence for the safety case.
>
>Bruce Slattery
>Manager Traffic Signals and UTC =3D20
>
>>>> david.harrison@xxxxxxxxxxxxxxxx 09/19/03 04:05pm >>>
>Sorry to come back, but the terms "sporting" and "chance" hardly seem to =
=3D
>be
>consistent with the science under which we all operate?
>
>David Harrison
>
>Parrett, Simon (19/09/2003 15:55):
>>I guess its a valid approach Graham, but it somewhat ducks the issue,
>>cyclists are still having to try and negotiate these junctions with or
>>without facilities. I do not think that ASL's encourage cyclists to use =
=3D
>the
>>pavement or cycle down the outside of traffic - (they do these anyway!).
>>There are lots of occasions where the carriageway width is not sufficient=
=3D
>=3D3D
>to
>>provide a proper cycle lane but cyclists can still make their scratchy =3D
>way
>>safely up the inside and into an ASL. I also have no problem with =3D
>multiple
>>lane / separately signalled approaches - again cyclists are using these
>>junctions with or without ASLs, at least with an ASL they have a sporting
>>chance.
>>
>>Simon
>>
>>
>>-----Original Message-----
>>From: Grahame Bath [mailto:grahame.bath@xxxxxxxxxxxxxxx]=3D20
>>Sent: 19 September 2003 15:16
>>To: tcug@xxxxxxxxxxxxx=3D20
>>Subject: [TCUG] Re: ASL's on multi-lane approaches
>>
>>
>>
>>I must agree entirely.
>>I
>>As one of the very few Traffic Systems Engineers also qualified as a Road
>>Safety Auditor,
>>recommendation is to only install ASLs where the chance of cyclists =3D
>moving
>>across the
>>lanes is minimal (otherwise they could be obscured by large vehicles).
>>
>>My view is that they should only be used on the most simple of approaches=
=3D
>-
>>and even then
>>with adequate space for an approach lane so not to encourage cycling on =
=3D
>the
>>pavement
>>or against the opposing flow.
>>
>>On no account would I recommend their use in the likelihood of vehicles =
=3D
>in
>>one lane running
>>at different speeds or times than the other. They should also only be =3D
>used
>>on straight
>>approaches 'cos otherwise you could encourage cyclists to come up on the
>>nearside of a
>>large turning vehicle. (ouch)
>>
>>Regards
>>
>>Grahame
>>
>>
>>~~~~~~~~~~~~~~~~~~~~~~~~
>>Grahame Bath
>>Senior Engineer, Traffic Systems
>>Traffic and Road Safety Group
>>Surrey County Council
>>
>>020 8541 7346 (Tel)
>>020 8393 6723 (Fax)
>>~~~~~~~~~~~~~~~~~~~~~~~~
>>
>>
>>Dave
>>An old quotation from TA 16/81, section 3.2 may help?
>>" A consistent system of signalling a given set of circumstances should =
=3D
>be
>>=3D3D3D
>>used
>>throughout the country. All displays must be clear and unambiguous."
>>
>>Under the Safety Audit process, some of our recent proposals for ASL's =3D
>have
>>been withdrawn on this basis. The underlying philosophy of " keep it
>>simple,
>>keep it safe" has been applied.
>>
>>Thanks
>>David Harrison
>>Safety Audit
>>Newcastle City Council
>>
>>
>>Dave Hulson (19/09/2003 13:14):
>>>Does anyone have any experience of ASL's on multi-lane junction
>>approaches?
>>>
>>>We have a proposed junction on an urban dual carriageway with a 30mph
>>speed
>>>limit and ramps combined with a plateau through the junction. Both dual
>>>carriageway approaches are three lanes wide with ahead, left and right
>>tur=3D3D3D>being permitted on both approaches. In one direction a nearsi=
de =3D
>cy=3D3D
>cle
>>lane
>>>will be provided and in the other direction there will be a shared bus =
=3D
>and
>>>cycle lane. The method of control that will be employed will result in
>>bo=3D3D3D>approaches displaying red signals for around thirty seconds out=
=3D
>of a
>>seven=3D3D3D>second cycle providing plenty of opportunity for cyclists to=
=3D
>get
>>ahead of
>>>queuing traffic.
>>>
>>>Opinion is strongly divided on the advisability of providing ASL's at =3D
>this
>>>location although the opinions are based on intuition rather than facts.
>>I
>>>would welcome any comments, preferably based on experience, that would
>>help
>>>to resolve this issue one way or the other.
>>>
>>>Thanks,
>>>
>>>Dave Hulson
>>>Traffic Signal Design
>>>Nottingham City Council
>>>
>>>
>>>######################################################################
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