ECN Forum Forums General Topics of the Trade General Discussion Area LED Traffic Signals

If I counted all the intersections with traffic lights within a 10 mile radius of my home the number would not fit on this forum.

The majority of these have been retrofitted with green, yellow, red, LEDs.

I saw a Rescue truck with LED beacons on it for the first time recently, they where very effective.

LEDs are showing up in some car tail lights also. You can spot them right away for the reasons Scott has mentioned, the quick on & off times.

Here in Las Vegas I'd say that ~90% of the red are LED, 75% of green and only a small handfull (probably a test) of yellow are LED based. All new signals are LED based, except for yellow. Most of the pedestrian signals are now LED based. We also are seeing more of the pedestrian signals that give a flashing hand with a countdown timer to when the traffic signal will turn from green to yellow. We still have a huge problem on "The Strip" with pedestrians crossing against the signal on red lights. The only way we have found to combat this is to elevate the crosswalks above the road...

Mike, I guess the "jay walkers" must be New Yorkers. We've elevated that stupdity to an art.

I wish we'd get pedestrian bridges at some of our more dangerous crossings also.

As far as LEDs are concerened, I've seen retro-fit LED clusters that are meant to replace incandescent brake and turn lights in cars. It's a mass of LEDs in a conical holder that's attached to a conventional bulb-base.

I'm glad I'm not the only one who finds these new traffic lights excessively bright at night...then again, it seems like car headlights have also been getting brighter. That's even worse.

Happy New Year y'all!

Maybe we'll see lights being fitted with a photocell and dimmer circuit as standard once LEDs are firmly established?

LOL! Well, I'm in rural area, and British intersections tend not to have lights as often as U.S. ones anyway.

The local car accessory shop has them here, along with LED bulbs specifically for backup lights which incorporate a beeper.

"Yes, folks, you too can annoy everybody within a 100-yard radius by having an annoying beeper when reversing just like the buses!"




[This message has been edited by pauluk (edited 12-31-2004).]

 
Paul, I don’t know for sure if pedestrian-crossing chirpers are Americans-with-Disabilities-Act originated, but they seem to be for assisting the ‘vision-deprived’ in street crossing.

For those with way too much extra time, or need reading material during a tedious alien abduction... {HP’s new frou-frou name is Agilent} www.agilent.com/about/newsroom/features/gettoknow/030102electronics.pdf
Studies by the University of Michigan Transportation Institute show that LED center high mount brake lights yield a 170-200 millisecond advantage in braking response time in favorable lighting conditions and a 300 millisecond advantage in poor lighting conditions due to their conspicuous, fast turn-on time.

…and www.agilent.com/about/newsroom/presrel/2004/10may2004c.html
…and www.lumileds.com/pdfs/techpaperspres/intertch2000.PDF

   ...y viernes nuevo habañeros, scott35.




[This message has been edited by Bjarney (edited 12-31-2004).]

Also, ever seen the strobe lights installed in some Fort Washington and York PA signals? They install them in the red signal visors and lead the wires through the gasket of the lense? It is a white, horizontal strobe light that flashes extreamly fast.

Ian
(Theelectrikid)

Glad you're still kickin' around!

The Chicago metro area's been changing over pretty heavily over the last 18 months, at least on state highways.

The only local town that's gone the LED route for walk/don't walk standards is Lake Forest (put your pinky up, gent's... they're high class, dont'cha know)

" a 300 millisecond advantage in poor lighting conditions due to their conspicuous, fast turn-on time."

At 60 mph that's a very valuable 26 feet.

A great thing I've noticed about our LED signals is that a section of the lamp can go out and the remainder remains lit, so the signal stays in operation instead of blacking out.

Talking about signals we have a weird one here in Winnipeg. Apparently its a special one that is designed to allow u-turns only. The signals manager was on the TV news a while ago saying its the only one that he knows of in Canada.

From looking at it I think that it is a special lens made up to go over a standard green led fixture. The lens looks like a
u-turn sign with a curved u and arrow pointing down small enough to fit on a signal head.

The intersection that it is on does not allow left turns (east) as its a one way street going west. Because of a shopping center 1/4 block down on the left side going north the traffic department had the idea of allowing traffic going south to make a signal protected u-turn to access it instead of putting in a median cut.

On the Alice Springs to Darwin railway line in the Northern Territory of Australia, all the level crossings (railroad crossings) are fitted with 12" LED lights. The equipment is solar powered (one crossing is ove 50km from the main electricity grid)