LED traffic light puzzler on NPRadio show..

[65535]

LED's IIRC have diminished throw in foggy conditions, it could be made up for in brightness but over a large distance it may be a little bit hard to see.

 

[Cyclops942]

LED's IIRC have diminished throw in foggy conditions, it could be made up for in brightness but over a large distance it may be a little bit hard to see.

We're talking about the first car in line at an intersection, here. This does not qualify as a large distance in my book.

 

[Diesel_Bomber]

There's also a very large difference between a light source being able to throw enough light towards an object to bounce light off that object so that the object is visible, and that same light source being viewed directly.

For example, my lowly Inova X1, on a clear night in good quality dark and with night adapted vision, has a useful range of roughly 30 feet. Now, that same X1, when used as a marker light in the same conditions, can easily be seen from well over a mile away.

:buddies:

 

[tvodrd]

The 0.1 second doesn't appear to be an issue in my neck of the woods. I drive to work in the dark every morning, and there's a ~1second delay between lights in one direction going red and the lights in the other direction going green. :shrug:

Larry

(I can add the cities could sure do a better job of synchronizing signals. The energy wasted, idlleing in line behind a red at empty intersections has to add up!!)

 

[gadget_lover]

Some intersections have a deliberate "all red" condition to combat the combinatoin of habitual red light runners and green light jumpers. The second or so allows all the cars to clear the intersection, even if it's a wide intersection and the car enters at the tail of the yellow.

It's a sick feeling to see a car enter an intersection an a yellow as the kid next to you guns it to make sure he is the first off the line as it turns green. There's nothing you can do but watch.

But back on topic....

I would take a red glowing lump of snow at traffic light height as a reason to stop. OTOH, I'd take that much snow as a reason to stay home.



Daniel

 

[Avatar28]

Here's the exact transcript of the answer.

TOM: Ohh, a few months from now I'm going to guess that would have brought us to winter.

RAY: Yes.

TOM: And in some parts of the country it gets cold and snowy.

RAY: And because these lights use so little energy they emit no heat.

TOM: Yeah.

RAY: And when wind blows snow and sleet and whatnot --

TOM: It stays right there. It doesn't melt it.

RAY: Exactly. And the old incandescent lights used to melt the snow. In fact, I talked to the chief traffic guru in Our Fair City of Cambridge, Jeff Morenti, and he said, oh yeah, this is a problem that nobody foresaw.

TOM: Of course. That's why we shouldn't live around here. Just another reason.