diamond geezer

 Saturday, January 21, 2012

Over the last year there's been a trial of Pedestrian Countdown signals at eight London road junctions. This is the Pedestrian Countdown at Traffic Signal Junctions road trial, or PCaTS for short. And it works like this...
  • Reduction in Green Man time to a standard 6 seconds (aligned to DfT guidance)
  • Increase in "Blackout" time (with a countdown timer)
  • Reduction in "All Red" time (to a standard 3 seconds, with a 2 second starting amber to traffic)
  • Increase in traffic green time (as a consequence of the above changes)
  • Green Man crossing time is reduced to the legal minimum. Countdown time is extended to compensate, but capped assuming a walking speed of approximately 1.2 m/s (2.7 mph) Cars can set off quicker, because it's easier to guarantee that pedestrians are off the crossing. And the main lights are green more often, which keeps the traffic moving for longer, which is what the Mayor and the motorist likes. At the Oxford Circus X-crossing the Extra Green Time for traffic is 61 seconds per hour, and at Finsbury Square 3 whole minutes.

    To check it's not pedestrians being royally shafted, the report accompanying the trial has some reassuring statistics. At the eight sites involved, the proportion of Red Man Time during the trial was 81%, compared to 82% before, so that's a slight improvement. Less reassuringly the Average Maximum Wait Time increased at Holborn/Kingsway by 3 seconds and at Tower Bridge by 7, whereas at Oxford Circus it decreased by 9. Swings and roundabouts.

    Yesterday TfL announced that the trial has been a big success, and so Pedestrian Countdown is to be rolled out at 200 further locations across the capital starting this summer. [map]
    The result of the on-street trial concluded that Pedestrian Countdown:
  • Had a positive response from the public - 83 per cent of those surveyed said they liked Pedestrian Countdown
  • Reduced uncertainty so more informed crossing decisions can be made
  • Will smooth traffic flow
  • Has no negative effect on pedestrian safety
  • Having used the system a fair few times, I'm with the 83%. It's good to know when the traffic's about to start moving again, and to adjust my intentions to match. I'm fit enough to dash across the road even when the Countdown's ticking down 4...3...2...1... and were I no longer as mobile I'd appreciate knowing precisely whether I did have time to hobble across or not. So bring it on, even if initially it's only at a very restricted number of sites. Countdown is progressing.

    If you like nerd-level transport statistics, graphs and tables, then you might appreciate reading the entire 39 page PCaTS report. If you don't have the time nor the inclination, here are ten potentially interesting facts gleaned from within.

    » On average, before the trial, pedestrians faced 9 seconds of Green Man Time followed by 9 seconds of Blackout. On average, during the trial they faced 6 seconds of Green Man Time followed by 12 seconds of Countdown. Same total, differently proportioned.
    » The average percentage of participants feeling safe increased across all sites from 73 to 91%.
    » It was found that fewer pedestrians felt rushed with the package of measures installed. On average across all sites the percentage feeling rushed decreased from 39 to 23%.
    » Irrespective of the type of crossing, the majority of pedestrians tended to cross as soon as possible after their arrival. Over 54% crossed within 5 seconds of arriving, 70% within 15 seconds and approximately 85% within 30 seconds, regardless of the pedestrian signals displayed.
    » A large percentage of pedestrians started to cross whilst the Red Man was showing: on average 68%, consistent with pedestrians being unwilling to wait.
    » With PCaTS, 33% of the pedestrians who sped up did so during the countdown: 12% did so in the first half of the Countdown and 21% in the second half.
    » There were significantly more (up to 12%) pedestrians still on the crossing 6 seconds before traffic gained priority, and up to 9% more on the crossing at the start of the traffic red/amber (i.e. at -2 seconds). However, this difference then rapidly reduced until there was no difference between crossing types at the point when the traffic signals changed to green (i.e. at 0 seconds).
    » There was some evidence that vehicles started to move forward slightly in advance of the green phase, in particular motorcycles and cyclists. This may be because they are able to use the Countdown displays as an indicator themselves.
    » The PCaTS study was completed in May 2011, but it's taken until January 2012 to announce that the trial was a success and will be rolled out further.
    » Of the 200 road junctions where PCaTS is being considered, there are none at all in Kingston-upon Thames, Ealing or Bexley, and only one or two in Hillingdon, Harrow, Richmond-on-Thames, Sutton, Barnet, Redbridge, Barking & Dagenham and Havering. The lion's share will be in Central London, especially Westminster and the City.

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