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gm2129 karma

Mickey's fans have to work, else they couldn't afford to set foot inside the park.

gm299 karma

Wait a second, 300 kcal = 1255.2 kjoules, this answer has a 25.52% margin of error! That is unacceptable and I will not approve your thesis on this subject.

gm221 karma

FYI, they are inductive loops, not magnetic. Small difference, I admit.

/also a traffic engineer

gm220 karma

The pedestrian buttons are designed to work thusly:

You press the button. That sends a signal to the controller that there is a ped who wants to cross the street. In most cases, it will wait until the time in the cycle when the corresponding vehicular movement is scheduled to get some green time. At that time, you will see the walking man sign on the pedestrian signal head to tell you when to walk.

What it won't do is stop opposing traffic early so that you can cross. It just lets the controller know that there is a pedestrian crossing the road, and that it should not allow the cross-street phase to terminate early if there are no cars there to use it. It will time your pedestrian interval so that you can cross the street.

But, if you are crossing the side street instead of the main street, it is likely that the main street was already going to get its full amount of green time anyway, so your pressing the button doesn't do much except show the walking man indication on the pedestrian signal head to tell you when it's safe to walk. The timing of the green intervals won't change.

I guess the answer to your first question is that it may change the operation of the signal a bit, if you are crossing the main street instead of the side street, but otherwise it doesn't change the operation of the signal much. Assuming that you are at a fairly heavily traveled intersection, at least. If you are at a signal where there is very light traffic, then you might get extra green time to cross as a pedestrian that normally wouldn't be given, because the streets at that intersection may not be programmed to allow so much green time for so few vehicles.

As for the weight sensors - they are used in some places, but they depend on the pedestrians standing at a known location, and they are prone to failure because people like to hit the button and then kind of mill around, and they may not stand on the correct spot to trigger the pedestrian phase.

gm218 karma

You heard right - in general, roundabouts are safer and more efficient than signals. If the driving population in your area is savvy to the roundabouts and how to navigate them, then they can be useful.

The reason you don't see more of them in America is that the typical driver isn't used to seeing them and they complain about the mere thought of implementing them. But studies show that they will reduce crashes, and there is the obvious benefit that they don't take any electricity to run and they don't go into flash in the morning rush hour to cause delays because of a power spike.

I think you'll see more and more of these being implemented, depending on where you live. In Texas, they are slowly becoming more popular.

Edit to say: it is important to light the roundabouts correctly, and design them to allow proper turning radius, and they do consume more right-of-way space than a signal does, in general, so those are also some reasons why they have been a little slow to show up. But I think going forward, there will be more of them because the benefits outweigh the costs.