[cstross]

It's not practical to design everything in the world with the very slowest people in mind. The efficiency losses would be huge. Imagine if every pedestrian crossing light went for five minutes. Vehicular traffic would grind to a standstill.

Actually, there was a study in the UK a couple of years ago that didn't get acted on, but which demonstrated that pedestrian crossing lights in British streets allowed so little time for crossing that able-bodied teenagers had to hurry -- middle-aged, elderly, unfit, or handicapped people really need about triple the time.

The solution is probably a combination of the sensor-controlled systems showing up in newer crossings in the UK (IR sensors block traffic by setting a red light until the crossing is clear) and cutting down on automobile use in densely populated areas like urban cores. Ahem. (Hint: why should your one ton rolling steel status symbol trump anybody else's right to use the highway?)

[bmsleight_]

The study was very flawed. The 85 percentile walking speed for pedestrians (1.2 m/s) is for when people start the crossing at the end of green man. So some 15 percent of the people are slower. However if youo take into account most people start crossing before the end of the green man, then the time is ample. "the sensor-controlled systems" - are hopelessly inefficient and actually confusing for pedestrians.

A countdown which displays the time until the red-man is best for a balance of all users.

[ciaranm]

The green man is intended as a sign that it's safe to _begin_ crossing the road - at least in the UK. You'll notice that the man changes away from Green long before the light sequence. That's intended.

[digi_owl]

In various places the green man will start to blink when there is seconds left before it changes over.

[Dylan16807]

Doesn't really matter. The takeaway is that the light timings don't have to change. You would just make the man stop being green earlier.

[landryraccoon]

How are you supposed to know how long it has been since the green man appeared? Presumably if it turned green while you were waiting, you would have started walking immediately. Do you have to wait until the next green man if you arrived at the intersection while the light was green?

[Dylan16807]

If you are particularly slow, then yes. This is equivalent to getting at the intersection only a few seconds later, not a big deal.