Newsgroups: sci.electronics Path: utzoo!utgpu!news-server.csri.toronto.edu!torsqnt!geac!gjetor!adeboer From: adeboer@gjetor.geac.COM (Anthony DeBoer) Subject: Re: Traffic signals Message-ID: <1991Apr25.201250.10438@gjetor.geac.COM> Organization: Geac J&E Systems Ltd. References: <111016.10481@timbuk.cray.com> Date: Thu, 25 Apr 91 20:12:50 GMT In article <111016.10481@timbuk.cray.com> rice@willow23.cray.com (Jonathan Rice) writes: >The gadget in use in St. Paul MN (don't know what brand it is) doesn't just >switch the colored signals. In addition, a bright white spotlight, about 1/3 >the diameter of the ordinary colored lenses, goes on in all four directions. >These lights are mounted on a little mast above the signal. > >I had always thought that this was to prevent boneheads from deciding that >the time was ripe for a right-on-red...but the quoted posting makes me think >it might also serve as confirmation for the onrushing emergency vehicle. > >The scheme has another advantage: I often see the white light before I see >flashers or hear a siren, and can prepare to pull over. A third advantage is that it confirms that the emergency-vehicle-detector was tripped, and makes it a bit more obvious if some bonehead :^) is tripping it himself with a strobe in order to get to work faster. If people see the white lights go on and nothing unusual goes through the intersection, they're going to start to wonder. -- Anthony DeBoer NAUI#Z8800 | adeboer@gjetor.geac.com | Programmer (n): One who Geac J&E Systems Ltd. | uunet!geac!gjetor!adeboer | makes the lies the Toronto, Ontario, Canada | #include | salesman told come true.