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From: RHB%MIT-MC@sri-unix.UUCP
Newsgroups: net.physics
Subject: physical laws of freeway traffic?
Message-ID: <2172@sri-arpa.UUCP>
Date: Wed, 15-Jun-83 11:56:00 EDT
Article-I.D.: sri-arpa.2172
Posted: Wed Jun 15 11:56:00 1983
Date-Received: Sat, 18-Jun-83 04:57:50 EDT
Lines: 23

From:  Robert H. Berman 


A good review of the models of traffic may be found in "Traffic
Science" edited by D.C. Gazis, 1974 (John Wiley).  The first chapter
deals with flow theories of traffic and introduces the hydrodynamic
model of traffic flow (shock wave propagation, acceleration waves,
lights, speed flows, density, etc) in both high density and low
density traffic regimes on highways.  It also talks about simple
statistical models. More sophisticated porbabilistic descriptions of
the gaps in traffic are discussed in other chapters. There is a rather
interesting dsicussion of the control problems in synchronizing
traffic lights.

Basically, in terms of the original question about stop-and-go
traffic, the hydrodynamic model would predict the occurance of
acceleration and deceleration density waves that the driver is
experiencing. The difficulty in driving is related as to where the
driver is and his motion relative to the shock front associated with
these waves. A driver should try to move so that any shock front is
stationary (in his frame) and that the average relative velocity
between him and his neighbors is minimized. In other words, "go with the flow",
not with the speed limit.