More traffic: roundabouts

[Robert Holmes]

In the traffic calming article I just posted, the author makes the point
that the 'shared space' approach that is being adopted in northern Europe
won't work in the US:
        " . many American traffic engineers say one critical ingredient is
missing for a system built around shared spaces to work in the United
States: a communal sensibility. "We live in a culture that gives so much
value to the individual and the expression of that is how we act in a car.
I'm not comfortable with less order when I can't get people to go below 50
or 60 miles per hour.""

This is graphically illustrated in a report by the Federal Highway
Administration "Roundabouts: an Informational Guide"
(http://www.tfhrc.gov/safety/00068.htm). In this, the claim is made (chapter
6) that: "To determine the speed of a roundabout, the fastest path allowed
by the geometry is drawn. This is the smoothest, flattest path possible for
a single vehicle, in the absence of other traffic and ignoring all lane
markings."

As anyone who has ever used a roundabout can tell you, the speed of a
roundabout is not related to your ability to hold the racing line; the
limiting factor is how well the roundabout manages the interactions between
its users. Maybe we should be approaching the US DOT with some agent-based
modeling proposals.

- rh


Dr. Robert Holmes
 
PO Box 2862, Santa Fe, NM 87504
mobile: [phone]
web: www.holmesacosta.com


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[Richard Harris-5]

With all this discussion GIS data and now roundabouts, I couldn't
resist.
 
http://www.gpsdrawing.com/gallery/land/magic_roundabout.htm 
 
Does driving this thing qualify as an NP-Complete problem, i.e. its
scales exponentially difficult with the number of cars? ;-)
 
-----Original Message-----
From: Robert Holmes [mailto:[hidden email]]
Sent: Thursday, May 20, 2004 9:06 AM
To: FRIAM
Subject: [FRIAM] More traffic: roundabouts
 
In the traffic calming article I just posted, the author makes the point
that the 'shared space' approach that is being adopted in northern
Europe won't work in the US:
" . many American traffic engineers say one critical ingredient is
missing for a system built around shared spaces to work in the United
States: a communal sensibility. "We live in a culture that gives so much
value to the individual and the expression of that is how we act in a
car. I'm not comfortable with less order when I can't get people to go
below 50 or 60 miles per hour.""
This is graphically illustrated in a report by the Federal Highway
Administration "Roundabouts: an Informational Guide" (
<http://www.tfhrc.gov/safety/00068.htm>
http://www.tfhrc.gov/safety/00068.htm). In this, the claim is made
(chapter 6) that: "To determine the speed of a roundabout, the fastest
path allowed by the geometry is drawn. This is the smoothest, flattest
path possible for a single vehicle, in the absence of other traffic and
ignoring all lane markings."
As anyone who has ever used a roundabout can tell you, the speed of a
roundabout is not related to your ability to hold the racing line; the
limiting factor is how well the roundabout manages the interactions
between its users. Maybe we should be approaching the US DOT with some
agent-based modeling proposals.
- rh
 
Dr. Robert Holmes
 
PO Box 2862, Santa Fe, NM 87504
mobile: [phone]
web:  <file:///\\www.holmesacosta.com> www.holmesacosta.com
 
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[Roger Critchlow-2]

Is this a roundabout or a crop circle?

-- rec --

Richard Harris wrote:
> With all this discussion GIS data and now roundabouts, I couldn't
> resist.
>  
> http://www.gpsdrawing.com/gallery/land/magic_roundabout.htm 
>  
> Does driving this thing qualify as an NP-Complete problem, i.e. its
> scales exponentially difficult with the number of cars? ;-)
>