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The Site => General discussion => Topic started by: rjluna2 on December 17, 2009, 09:08:44 PM

Title: AJC - Cool Traffic Lights a Hazard
Post by: rjluna2 on December 17, 2009, 09:08:44 PM
The Atlanta Journal-Constitution, Wednesday, December 16, 2009

Page A12

Cool Traffic Lights a Hazard

By Dinesh Ramde, Associated Press

Milwaukee - Cities around the country that have installed energy-efficent traffic lights are discovering a hazardous downside: The bulbs don't burn hot enough to melt snow and can become crusted over in a storm - a problem blamed for dozens of accidents and at least one death.
   Many communites have switched to LED bulbs in their traffic lights because the use 90 percent less energy than the old incandescent variety, last longer and save money.  Their advantage is also their drawback: They do not waste energy by producing heat.
   Authories in several states are testing possible solutions, including installing weather shields, adding heating elements like those used in airport runway lights, or coating the lights with water-repellent substances.
   Short of some kind of technological fix, "as far as I'm aware, all that can be done is to have crews clean off the snow by hand," said Green Bay, Wis., police Lt. Jim Runge.  "It's a bit labor-intensive."
   In St. Paul, Minn., for example, city crews use air compressors to blow snow and ice off blocked lights.
   Some communites began installing coll-burning LEDs more than a decade ago, and it wasn't long before drivers started complaining about the problem.
   Exactly how much a technological fix will cost is unclear, but it will surely cut into the savings and the energy efficeny many cites are enjoying.
   Wisconsin, which has put LED bulbs at hundreds of intersections, saves about $750,000 per year in energy costs, said Dave Vieth of the state Transportation Department.
Title: Re: AJC - Cool Traffic Lights a Hazard
Post by: rjluna2 on December 17, 2009, 09:13:14 PM
Opinion / Suggestion for LED Traffic Lights in Snow Belt area.

I suggest you (Department of Transporation, Public Works, and et. al) at start of the winter season, at least install one light complex for each direction fitted with incandescent light bulbs for safety feature.

When the winter season is over, you can always reinstall LEDs for the remaining year.
Title: Re: AJC - Cool Traffic Lights a Hazard
Post by: Lil'Cinnamon on December 18, 2009, 01:23:43 AM
The traffic light i found on the ground, is LED. and it sure doesn't get hot at all. i can tell this is a hazard! BUT, people should get the fact, if they cannot SEE the light, or if it is out, treat it as a 4 way stop. even on a highway when people usually go fast.
Title: Re: AJC - Cool Traffic Lights a Hazard
Post by: Vince on December 18, 2009, 05:12:58 PM
Yeah, when traffic lights are defective, the intersection becomes a 4-way stop. If possible, flashing red lights replace the lights' program.
Title: Re: AJC - Cool Traffic Lights a Hazard
Post by: Medved on December 19, 2009, 01:27:29 PM
The issue is, then such failure mode (snow cover) is not handled by the controller (unlike the burned out filament).
I think this only reveal the flaw of about this signaling: When it is not readable from some side, the safety rely to the people responding in the proper way (4-way stop,...), instead of driving like they are used to.
The danger could be mitigated only by proper publicity about safe behavior in such nonstandard situations.
I've met people, especially in US, saying: The sign say 55mph, so i assume it is safe to drive such speed, why i should care about weather? And it was strong freezing rain...

And to improve the situation technically, the easiest and most efficient would be to add heaters...
Title: Re: AJC - Cool Traffic Lights a Hazard
Post by: rjluna2 on December 19, 2009, 05:15:10 PM
Yeah, when traffic lights are defective, the intersection becomes a 4-way stop. If possible, flashing red lights replace the lights' program.
The problem is that there may be prevailing wind in certain direction that could cover one part of the direction of the traffic signal.  There is no way that the driver would know the other direction may be masked.
Title: Re: AJC - Cool Traffic Lights a Hazard
Post by: Medved on December 20, 2009, 04:07:56 AM
If i remember well (i'm living in Europe, where "4way stop" system  is not used, so i do not know the law exactly in all details), the "4way stop" mean you have to wait, till all approaching cars stop before proceeding. So if your light is blocked, you stop and wait for other direction to do so as well. If the other direction does not stop, they have likely green, so you would have to stop anyway. If the other direction is stopped on their RED, you just continue after your stop. And if you see approaching car from the distance, you have to be able to judge, if it is safe to proceed before it arrive, otherwise just keep standing and wait, what it would do.
Following this no severe accident could happen.

By the way on most places in US i've seen signal lights BEHIND the crossing, so you are able to see, what is signaled to other directions as well, so i think it is easy to judge, what to do, when "your" signals do not work.