[TCUG] Re: Puffin Crossing Clearance Periods

I have experienced horrific pedestrian accident rates with Pelicans on urban
dual 3s as buses in the nearside lane obscure late crossing pedestrians.
Puffins should overcome this problem.

 Dick

> -----Original Message-----
> From: Dave Hulson [SMTP:dave.hulson@xxxxxxxxxxxxxxxxxxxxx]
> Sent: 12 December 2003 11:41
> To:   tcug@xxxxxxxxxxxxx
> Subject:      [TCUG] Re: Puffin Crossing Clearance Periods
> 
> Thanks for you comments David.  However, one of the problems that I am
> anticipating at the crossing I described is the problem of pedestrians
> continuing to cross well after the appearance of the red man.  At the
> existing crossing some pedestrians appear to take vehicles moving off as
> the
> signal to consider waiting at the kerb.  With this behaviour I can forsee
> the 'clearance' period being used up by pedestrians who started to cross
> well into the clearance period which becomes a bit self defeating if the
> justification for this extendable period is enhanced safety.
> 
> I agree with you about Ian's suggestion which would result in period 6
> being
> increased to 14 seconds and period 7 being reduced to 1 second which
> leaves
> the potential maximum and minimum delays unaltered.
> 
> Dave Hulson
> Traffic Signal Design
> Nottingham City Council
> 
> 
> -----Original Message-----
> From: tcug-bounce@xxxxxxxxxxxxx [mailto:tcug-bounce@xxxxxxxxxxxxx]On
> Behalf Of Key David
> Sent: 12 December 2003 11:22
> To: 'tcug@xxxxxxxxxxxxx'
> Subject: [TCUG] Re: Puffin Crossing Clearance Periods
> 
> 
> 
> Isn't the point here that Puffins aim to give peds as much (or as little)
> time to cross the carriageway as they need.
> 
> Unless the crossing is very busy with peds (i.e. In the City Centre /
> close
> to a Bus or Railway  Station) where the pedestrian demand is such that
> they
> are likely to continue crossing long after the red man appears, the OCD
> should allow the crossing to return to the traffic as soon as it is safe
> to
> do so (i.e. when the peds have cleared the crossing) and should therefore
> seldom run up to the maximum clearance.
> 
> I got the impression that when Ian was talking about periods 6 & 7, he was
> suggesting that setting period 7 to 1 sec and adding the other two seconds
> to period 6 gives a crisper change whilst leaving the clearance period the
> same, as it will not then stick 3 seconds on the end of the clearance
> period
> regardless of OCD i/p.
> 
> David Key
> Traffic Signals Design
> Sheffield City Council
> 
> 
> -----Original Message-----
> From: Dave Hulson [mailto:dave.hulson@xxxxxxxxxxxxxxxxxxxxx]
> Sent: 12 December 2003 10:21
> To: TCUG (E-mail)
> Subject: [TCUG] Puffin Crossing Clearance Periods
> 
> 
> I am currently looking at the provision of a pedestrian facility across a
> busy dual carriage way.  In looking at the consequences of choosing to
> provide a puffin rather than a pelican crossing, the big difference is
> obviously the potentially far longer clearance period following the green
> man that results from using a puffin.
> 
> At the 9m wide crossing that I am looking at, typical timings for a
> pelican
> following the green man would be:
> 
> Period E - 2 seconds flashing green man / red to traffic,
> Period F - 7 seconds flashing green man / flashing amber
> Period G - 1 second red man / flashing amber
> 
> before the traffic received a green signal.  This would give a minimum
> delay
> to traffic following the green man of 2 seconds and a maximum delay of 10
> seconds.
> 
> At a comparable puffin crossing, the equivalent timings would be:
> 
> Period 5 - normally 1 sec all-red
> Period 6 - 0 to 12 sec all-red based on advice in LTN 2/95
> Period 7 - normally 3 sec all-red
> Period 8 - normally 1 sec all-red
> Period 9 - fixed at 2 sec red/amber
> 
> before the traffic received a green signal.  This would give a minimum
> delay
> to traffic following the green man of 4 seconds and a maximum delay of 18
> seconds.
> 
> It seems inconsistent that two facilities, each designed for the same
> purpose and following the current advice for each facility, should produce
> such different results.
> 
> Now to come to the point!  LTN 2/95 states that period 6 should NORMALLY
> be
> set so that periods 6 and 7 together equal 5 + 1.67 (the length of
> crossing - 3 metres) and it is this which produces the potentially long
> clearance periods.  At JCT Traffic Signal Symposium this year, Ian
> Routledge
> gave a very interesting talk on puffins (The Devil is in the Detail) in
> which he advocated, amongst other things, tuning the timings of crossings
> to
> give 'crisp' operation.  Does anybody have any views on 'tuning' period 6
> at
> puffins to give a maximum clearance period that lies somewhere between the
> value that a pelican would give and the value that a 'standard' puffin
> would
> give?
> 
> At junctions it is permitted to use nearside pedestrian signals with no
> on-crossing detection and so it would not seem unreasonable to provide
> pedestrian crossings which have an element of extendable all-red, but
> maybe
> not to the extent originally envisaged.
> 
> Any thoughts or actual experiences would be appreciated.
> 
> Dave Hulson
> Traffic Signal Design
> Nottingham City Council
> 
> 
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