Urban power outages are a not-infrequent occurrance here in the US, especially in areas prone to wind, ice storms (e.g. New England), or market failure (e.g. California). Unfortunately, when the power goes out, traffic lights often go dead, too. Drivers are supposed to treat dead-light intersections as four-way stops, but this doesn't seem very safe to me, and in any case can cause serious traffic delays.

Why not put a small battery in traffic signals so that they can remain on for at least 3 days or so after the power goes out? Most urban power outages last only a few hours. This is especially feasible with low-power LED lights, and/or a solar-panel assist (panels which could also be a distributed power source during normal operation).
-- beland, Jun 24 2003

Countdown to Change of Light's Status http://www.halfbake...20to_20Go_20signals
Can this be included? [Zimmy, Oct 17 2004]

Less Lights Concept http://www.halfbake...e_20Traffic_20light
See above Link, maybe Double Light? [Zimmy, Oct 17 2004]

I like the idea. +
-- DarkRanger, Jun 24 2003


I'm very surprised this isn't done. The batteries could even be solar charged.
-- 2 fries shy of a happy meal, Jun 25 2003


Just a good rounded idea. Not much to argue against, lol
-- DarkRanger, Jun 26 2003


In some cities the traffic lights are on their own grids. Oddly enough, so are trolley buses. In Vancouver, two years ago, it was distinctively eerie to be surrounded by complete darkness during a massive blackout, yet still hear the whush of a passing bus.

That was a neat night. We were testing some sound equipment at the time, and we thought we caused it!
-- rapid transit, Jun 28 2003


This may have value in an urban enviroment, but in the countryside the traffic flow improves when the lights crap out. They put them up out here to keep their cronies in jobs.
-- LabRat, Jun 28 2003


See Links. I think the 3 of these Ideas ought to be the traffic light of the future!
-- Zimmy, Jun 29 2003



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