Almost every weekend we walk over to our favorite cafe for breakfast. On Sunday I noticed this traffic light on our way home. We were walking on the opposite side of the street from this light, and as we approached the corner I looked up and the lights seemed to have a tall thin shape. I thought, how odd. As we walked through the intersection, I happened to look up again, and now they looked perfectly round. I realized it was just an optical illusion. As we reached the far side of the intersection I looked again, this time they looked short and fat.
I don’t recall ever noticing this on any other traffic light. You have to be standing dead-center for them to look round. If you’re off to either side, even a little, they totally change shape. That’s just weird.
You know why they do that, right?
Do you mean… do I know what causes the illusion? Ironically, I didn’t give it much thought, but if I had to guess I would say because it’s shaped like this (when viewed from the top):
If you mean… Do I know why they make them this way? I have no idea.
They make them like that to make it harder (ideally, impossible) for people like me who, when approaching an intersection, try to anticipate when the light is about to change to green in my direction by looking at the traffic light for the cross-traffic to see if it’s yellow and about to turn red. The angle on the light should be blocking it from the oncoming crosstraffic. Does that make sense?
Ah, ha… I see. I did not know that. Thanks for the info.
May be it depends on visual angle? I think so.