🚀 go-pugleaf

On Tue, 28 Sep 1999 18:10:22 -0400, X Metro Man <pdcorc@excite.com>
wrote:

>On 28 Sep 1999 20:40:06 GMT, Kiki <tigress@havoc.gtf.org> wrote:
>
>>*nod* I like trip plates a lot. I don't think they would work so well in
>>the busy downtown, but outside of it there are plenty of intersections
>>where trip plates are really nice. There are some intersections though
>>where the trip plate is farther back to allow for some accumulation, my
>>aunt would slow down at the area and then get a green before she got to
>>the light.
>
>Trip plates mean you stop often.  

Just as a point of information, of the many ways to detect the
presence of vehicles at an intersection, none of them involve
"plates." ;-) Current detector types include:

Induction loop
Transponder
Magnetometer
Ultrasonic
Microwave
Infrared
Rubber tube
Tape switch
Triboelectric
Piezoelectric
Optical

Around here the detectors are usually the induction loop type, which
is a loop of wire embedded in the road surface. The loop is part of a
resonant circuit at around 100kHz; any metallic body in close
proximity to the loop will change this resonant frequency and thus
indicate the presence of a vehicle. Usually there are 3 or 4 loops in
each lane at the intersection itself (which gives an indication not
only of the presence of vehicle(s) but a rough indication of how
many), as well as an additional loop approximately mid-block (to
detect approaching vehicles).

You're correct about the "stop often" part, however. ;-)