1998-12-09 - Re: No Subject ( camera nonsense )

Header Data

From: Michael Motyka <mmotyka@lsil.com>
To: Lucky Green <shamrock@cypherpunks.to>
Message Hash: e21d2cab902db7407e6dbc8abd84a1e303e18e9f3e51de1de8991b2f1076fc8a
Message ID: <366EF650.B19@lsil.com>
Reply To: <Pine.BSF.3.96.981209194307.12228A-100000@pakastelohi.cypherpunks.to>
UTC Datetime: 1998-12-09 23:13:04 UTC
Raw Date: Thu, 10 Dec 1998 07:13:04 +0800

Raw message

From: Michael Motyka <mmotyka@lsil.com>
Date: Thu, 10 Dec 1998 07:13:04 +0800
To: Lucky Green <shamrock@cypherpunks.to>
Subject: Re: No Subject ( camera nonsense )
In-Reply-To: <Pine.BSF.3.96.981209194307.12228A-100000@pakastelohi.cypherpunks.to>
Message-ID: <366EF650.B19@lsil.com>
MIME-Version: 1.0
Content-Type: text/plain

Lucky Green wrote:
> Traffic analysis is performed using wire loops in the the road. The
> sensors mountend on overpasses near truck scales fulfill a different (so
> far unknown) purpose.
> --Lucky
The wire loops I know about use 60Hz AC and measure inductance. I 
believe that this would make them unsuitable as speed measurement
devices since measurement would extend over a number of cycles. They
might work if they were widely separated but you would have to be sure
there was only one vehicle generating the peaks.

I'd stick with the speed detector radar for now to explain the overhead