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From: jawa@ihuxl.UUCP (James A. Wadas)
Newsgroups: net.auto,net.analog
Subject: Re: Spoofing traffic signals
Message-ID: <1799@ihuxl.UUCP>
Date: Mon, 12-May-86 13:54:32 EDT
Article-I.D.: ihuxl.1799
Posted: Mon May 12 13:54:32 1986
Date-Received: Wed, 14-May-86 12:00:59 EDT
References: <840@ihu1h.UUCP>
Distribution: net
Organization: AT&T Bell Laboratories
Lines: 23
Xref: watmath net.auto:10512 net.analog:822

> x
> 		    Spoofing Traffic Lights
> 
>    Here's the scenario:
> 
>      I'm stopped at an intersection, waiting for  the  light
>      to	 turn green. No	one else is around.  The light seems
>      to	be red for an eternity,	but there's no traffic.
> 
>    I back my truck up a	few feet, off the sensor loop buried
>    in  the  roadway,  then  drive  back	 over the loop a few
>    times.  This	will usually cause  the	 traffic  signal  to
>    become green.
> -- 
> ===============================================================================
> Bob Parnass,  Bell Telephone Laboratories - ihnp4!ihu1h!parnass - (312)979-5414

Photovoltaic cells sometimes react when you "flash your brights" 
on an upcoming traffic signal so equipped.  Deserted intersections
at twilight provide the best conditions for this phenomenon.
-- 
James Wadas @ AT&T Bell Laboratories -- Naperville, Illinois
(312) 979-0240 ...!ihnp4!ihuxl!jawa