Path: cantaloupe.srv.cs.cmu.edu!magnesium.club.cc.cmu.edu!news.sei.cmu.edu!cis.ohio-state.edu!zaphod.mps.ohio-state.edu!usc!rand.org!edhall
From: edhall@rand.org (Ed Hall)
Newsgroups: sci.electronics
Subject: Re: Los Angeles Freeway traffic reports
Message-ID: <16711@rand.org>
Date: 21 Apr 93 20:22:51 GMT
References: <C5sLMB.9w6@cup.hp.com> <C5uLqn.Gpw@fc.hp.com>
Sender: news@rand.org
Organization: RAND
Lines: 29
Nntp-Posting-Host: ives.rand.org

In article <C5uLqn.Gpw@fc.hp.com> cfb@fc.hp.com (Charlie Brett) writes:
>: While driving through the middle of nowhere, I picked up [KNX], AM 1070,
>: a clear-channel station based in Los Angeles. They had an ad 
>: claiming that they were able to get traffic flow information from 
>: all of the thousands of traffic sensors that CalTrans has placed
>: under the pavement. Does CalTrans sell this info? Does [KNX] have
>: an exclusive? What's the deal?

Well, they claim they are the only radio broadcaster with this
information.  But the city's cable channel (35 in CableVision areas)
shows this information map during travel times (6-9am and 4-7pm, I
believe).  Most of the major LA freeways are covered.  The
computer-generated map shows green, yellow, red, or flashing red
(respectively: <40mph, 25-40mph, >25mph, and "incident"--I might be off
a little on the speeds, since this is from memory).

I often look at this display in the morning to see if I really want to
fight the traffic on the Sepulveda Pass or work from home for a little
while to wait for it to clear.

Another poster explained the origin of the information: sensors (embedded
wire loops) in the pavement near ramps and every half mile or so.  CalTrans
has had a "big board" driven from this data in their traffic control center
for some time.  I don't know if they are selling the data or if anyone
with the equipment necessary for its transmission and display can have
it.

		-Ed Hall
		edhall@rand.org
