Rob is blowing a whistle, over and over.
Bob: “Why are you blowing that whistle, Rob?”
Rob: “To keep the dragons away.”
Bob: “I see no dragons.”
Rob: “It works!”
Rob is blowing a whistle, over and over.
Bob: “Why are you blowing that whistle, Rob?”
Rob: “To keep the dragons away.”
Bob: “I see no dragons.”
Rob: “It works!”
Some of these actually do have an effect, but it’s difficult to impossible for a person to know whether this particular one is a placebo button or not.
This is especially the case with elevator close door buttons. Those buttons are always hooked up, because they are needed during emergency operation with the fireman’s key. They are sometimes programmed to cycle the doors marginally faster under normal circumstances, but more often aren’t.
Also, some of the traffic crossing buttons don’t make the walk cycle come sooner, but they occasionally are needed to insert a walk cycle at all, because some intersections don’t trigger a walk cycle unless the button has been pressed.
Some? In my area all the lights require a button press for a walk cycle. Even if the traffic lights turn red for the cars (e.g. in an intersection for cross-traffic), the pedestrian lights will stay red too unless the button was pressed.
Certainly around my area in a UK city there are plenty which automatically go to a green man even if no button was pressed. This is usually the case on more complicated intersections where in order to keep traffic flowing correctly that pedestrian crossing would be free at some point anyway, so they just put the green man cycle on by default. Of course they still put a button for pedestrian-satisfying reasons!
There is a set of lights near me at a cross roads which has an extra stream of traffic comkng from a row of shops off one of the roads so theres north south traffic, east west traffic and then traffic from the west that came from a little side road and out of the west entrance. If that makes sense. So 3 states the lights can be in.
Anyway, the lights are automatic, they cycle in the same pattern around the 3 states and the walk/cycle pedestrian lights follow that pattern. However, if a pedestrian presees the button, then after the extra stream of traffic from the shops has gone, an extra state is added where no cars can go in any direction and all of the pedestrian walk/cycle lights come on briefly allowi g pedestrians to cross in all directions.
Always found that mildly interesting.
In my area (San Francisco Bay Area) it depends on how much pedestrian traffic is expected. I live in the suburbs and, as I said, the walking light only goes on if the button is pressed. But if I go to San Francisco itself, lights are all on a timer (and there are no buttons at all).
I think you have the elevator example crossed. My random testing suggests the door open button always works. The close button sometimes is as you say, just to make people feel like they have a measure of control.
I think I’ve only seen one elevator that didn’t do anything immediately after pressing the close door button.
I think traffic lights depend on the skill of the person setting them up. They’ve got a bunch of sensors (car waiting over magnetic sensor, visual sensor detects something other than road in magic area, pedestrian button pressed, time of day, timer since last transition, emergency vehicle override) as input and different intersection states as output.
Someone could program a cycle to just ignore all of the sensors and run through the various states on a timer. Or they could make a more complex cycle loop that lengthens the main state at night, switches sooner if a sensor is triggered, and tries to be smart about it. Or you could go for an even more complex statistical model that not only takes sensor states into account but tries to predict those sensors for even more accuracy.
My guess is that there’s great variance in both the skills of the person doing the programming and their managers and politicians/administrators calling the shots. And that variance in skill includes ones who don’t bother trying anything more complex than the defaults as well as those who do but aren’t good at it (eg: I’ve noticed that some intersections make their main cycle longer at night and don’t cycle unless someone is waiting but make them wait longer than they would during the day when night time means that interrupting the main cycle affects fewer people so they make people wait on the side streets for no good reason).
And there’s also the question of persistence. If they need to be reprogrammed any time the power goes out, they might just go with the easier route if they can’t restore backups.