13

This has baffled me for a long time: why pedestrian crossings are installed in the UK with two sets of cross / don't cross indicators - one above the other.

On this set I saw recently it's not even consistent: at one end of the crossing there are two indicators - and at the further end there's just one !

Can anyone shed any light on this - is there some obscure accessibility reason for doing this ?

(BTW The 'walking' man lights up green when the traffic stops. Each indicator makes sense from a UX point of view. It's just that there are two of them)

Pedestrian Crossing Indicators

  • An interesting thing I noticed too is that the indication is on the road side of the pedestrian (before crossing). Where I live at least its always on the other side of the road (or on both sides but oriented so you check the other side). – Alvaro Oct 23 '16 at 11:06
  • I think it has something to do with disability...wheelchair user heights possibly. Just guessing. – user92642 Oct 23 '16 at 13:17
  • 3
    Putting it on the same side as the pedestrian is a new thing they've started doing over the last few years. Personally I think its bad design as if it's on the other side of the road you can watch the traffic AND the indicator at the same time to check for any vehicle who is trying to jump the lights. – PhillipW Oct 23 '16 at 16:56
  • @PhillipW: I've noticed that at some intersections, "No Turn On Red" signs are on the near signals's post rather than on the one across the intersection that's actually in view when stopped. Very bad design. – MMacD Jan 16 '17 at 17:28
11

I have found this documented in an official document from 1995 named The Design of Pedestrian Crossings . Specifically (but not limited to) the following items:

5.1.5 Drivers must have a clear view of at least one signal head on approaching, and when stationary at, the stop line. Where the view of the vehicular signals is reduced by the vertical or horizontal alignment of the road or other situations such as masking of signals in heavy traffic conditions or by overhanging trees, the conspicuity should be enhanced. This can be done, for example, by the provision of additional secondary heads, tall posts, building out kerb-lines if the carriageway width is sufficient or installing signals over the carriageway. Such overhead signals should be considered as supplementary to and not replacements for those listed as minimum in the relevant Regulations. If the overhead signal option is to be considered the problems of maintenance should be taken into account.

And....

5.1.7 To assist blind and partially sighted pedestrians, as they approach the crossing, the primary push button/indicator panel should normally be located on the right hand side. The alignment should encourage them to face oncoming vehicles. The centre of the push button should between 1.0 and 1.1 metres above the footway level.

And...

5.1.8 At Toucan crossings it is normal to install a push button unit either side of the crossing place at the height quoted above. Special arrangements may be needed if an equestrian push button is required.

Therefore...

The lower one (as mentioned in another comment) is to allow all users, including handicapped ones, to see and interact with controls at their own accessibility level, while the other is to allow all other users have a clear view. Think of a crowd of pedestrians, then both signals: If you had only the lower one, people at the back and drivers wouldn't see the signal. If you had only the higher one, short people on the back wouldn't see the signal either. Thus, you need both of them

Practical Testing

Here's a case that may happen with users with disabilities, handicapped or simply small height (such as children or people with dwarfism conditions). Please note the visual angles (in this example I considered all this people has the widest possible visual angle, around 75 degrees)

enter image description here

As you can see, it would be very difficult for a person in a wheelchair to see the upper sign. Similarly, second and third person in the row won't see the lower sign

  • 1
    I think 5.1.5 applies to the traffic lights controlling the drivers though, not those controlling the pedestrians. The official document gives the height of the push button. But still doesn't explain the existence of the double set of pedestrian indicator lights - nor why they are only installed on one side of the road ! – PhillipW Oct 24 '16 at 7:31
  • Having read the linked document I can see that this is a type of "smart" pedestrian crossing with sensors - called a "Puffin" ( you can just see the two black boxes on the pole on the other side of the road ). idgo.ac.uk/pdf/PedestrianCrossings.pdf – PhillipW Oct 24 '16 at 13:42
  • Thanks for adding the fields of view diagram. I think this possibly is the theory which drives the design of the whole crossing - that one can see the indicator at the same time as viewing the traffic. However in practice it seems a fundamental design flaw to me. You only have 'one point of vision' and if it's looking at an approaching car, its not looking at the indicator (in practice we flick our viewpoint around the whole time and change our focus from far to near). – PhillipW Oct 25 '16 at 7:36
  • Comprehensive answer! – DarrylGodden Jan 13 '17 at 20:45
1

My guess is that the side of the road the picture is taken from, might be busy at certain times and therefore the lower signal not seen.

So an extra higher signal helps people who are farther from the post and might have others standing in front of the lower one.


So my impression is that in order to provide solution to some problems as @Devin indicates, new problems arise and this is a solution to the second ones.

  • The photo is actually taken from an 'island' in the middle of the road (there are two sets of lights to cross the road). I guess there's some sense to the 'people standing in front of the lower indicator' idea. But people could also stand in front of the one at the other end of the crossing where there isn't the double indicator ! – PhillipW Oct 23 '16 at 17:00

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.