From: John Woodgate
Subject: Re: Smart traffic lights
Date: Fri, 3 Jan 2003 13:44:57 +0000
Organization: JMWA Electronics Consultancy
Reply-To: John Woodgate
NNTP-Posting-Date: Fri, 3 Jan 2003 15:12:22 +0000 (UTC)
X-Newsreader: Turnpike (32) Version 4.01 <5Z8C9wtxbnpWyFnyfFzqmVF739>
I read in sci.electronics.design that Robin
wrote (in <firstname.lastname@example.org>) about 'Smart
traffic lights', on Fri, 3 Jan 2003:
>This may be a UK thing only but traffic lights here have the habit of
>changing for no reason. Through-traffic will be moving along nicely
>and then suddenly the lights will change. Everything stops. And waits.
>Nothing happens on the green-light side, no traffic, nothing and then
>equally as suddenly the lights change back.
There is a sort of watch-dog timer that puts a set to green (and the
intersecting one to red, of course), even if no vehicle has been
detected. This used to allow for vehicles (bicycles) that were not heavy
enough to work the pneumatic detector pads. Sometimes we had to stamp
on the pad to get the lights to change.
Now that the detectors are induction loops, it may be that some horse-
drawn vehicles don't have enough metal in the right place to work them.
Then there are wooden bicycles...
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
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