Private Toll Roads

Article in NY Times about experience of privatization on Indiana Toll Roads: Toll Road Offers New Jersey a Fiscal Test Drive . While noting critics, the article is generally favorable. This is an issue primarily for existing public toll agencies which a number of governors want to sell off for cash up front. Secondarily, the issue arises of tolling existing untolled roads and building new private toll roads.
The article did not raise the issue of non-compete clauses, which were the undoing of California SR-91’s private ownership.

Metcalfe’s Law, Accessibility, and Zipf

Bob Metcalfe, Inventor of the Ethernet, famously proposed that the value of a communications network is given by n^2, where is n is the number of members on the network. This has been dubbed Metcalfe’s Law.
In an article published in IEEE Spectrum titled Metcalfe’s Law is Wrong, my colleague Andrew Odlyzko with Bob Briscoe and Benjamin Tilly reason from Zipf’s Law (using Zipf’s Law applied to word frequency, but as transportationists, we could just as easily use Zipf’s Law as applied to city size distribution) why this is not the case, and that n log(n) is a better estimate. In short, not every connection is equally valuable. This is something well understood in transportation, where accessibility measures discount connections by a function of their travel impedance. However this article suggests there is something else going on, that there are, in a sense, diminishing returns to connections. The first connection is more valuable than the second.
One could organize this over time instead of just network size, and suggest that network value grows at a decreasing rate as all the best connections are made first, then the next best connections, and so on.
If this is the case, this generates the hypothesis (which I have not yet tested) that in a hedonic model of price (value) of real estate, accessibility measured as a product of the log of activities will give a better fit than one which just uses activities straight. (Results of hedonic models suggest accessibility is a significant factor in explaining house price, see Access to Destinations: Development of Accessibility Measures (esp. Chapter 5) for an example ).
Traditionally we represent Accessibility (Hansen’s Accessibility Measure) at point i (Ai) as proportional to Destinations at j (say employment Ej) multiplied by f(Cij) where Cij is a travel cost, and f(Cij) is a travel impedance function (e.g. I/Cij^2) in the classic gravity model or e^(B*Cij) using a negative exponential form B<0).
Ai = ∑ Ej * f(Cij)
but the n log(n) argument suggests
Ai = log(∑Ej * f(Cij) )
might give a better fit in a behavioral or hedonic model dependent on accessibility.
(in short we discount the job for its difficulty to reach before we discount it because of diminishing returns. )

The danger of rail

A wonderful quote turned up on the website: The Ponderings of Woodrow: on a blog post about bad predictions:
“Dear Mr. President: The canal system of this country is being threatened by a new form of transportation known as ‘railroads’ … As you may well know, Mr. President, ‘railroad’ carriages are pulled at the enormous speed of 15 miles per hour by ‘engines’ which, in addition to endangering life and limb of passengers, roar and snort their way through the countryside, setting fire to crops, scaring the livestock and frightening women and children. The Almighty certainly never intended that people should travel at such breakneck speed.” — Martin Van Buren, Governor of New York, 1830
Another from a page:;>Famous Authoritative Pronouncements

“Rail travel at high speeds is not possible because passengers, unable to breathe, would die of asphyxia.”
Dionysius Lardner, Professor of Natural Philosophy and Astronomy at University College, London, and author of The Steam Engine Explained and Illustrated
Great Quotes from Great Skeptics
“What can be more palpably absurd than the prospect held out of locomotives traveling twice as fast as stagecoaches?”
– The Quarterly Review, England (March 1825)

Another player in traffic information

From New York Times: Microsoft Introduces Tool for Avoiding Traffic Jams
The key components for any valid system is data. In most cities, there is no real traffic information on side streets. Developing “personalities” for streets is a nice idea, but without real-time data, it is all guess work.
Bill Gates got his start creating traffic counters, with his company Traf-O-Data, so this may be an idea dear to his heart.

Do Trash Cans Induce Garbage?

From the San Francisco papers a while back, I saw a headline “”City rids streets of hundreds of garbage cans: Mayor says high number led to trash overflows””
An article about this: Trash cans cut back on city streets / Mayor defends policy but supervisors, residents complain
On its face, eliminating garbage cans will not eliminate garbage, so what is the mental model Mayor Newsom has?
(a) by increasing the transportation cost of disposal, people will create less waste? (The induced demand argument.
(b) people/businesses are free-riding on public trash receptacles, and that by cutting back, people will fund their own receptacles?
The question needs to be asked why were public trash receptacles initially deployed? One suspects public dumping of waste and littering were problems, otherwise a solution would never have been proposed. Public dumping and littering are not mere aesthetic issues, there is also a significant public health problem. To sustain a large population in a small area, waste must be managed.
The example of Amsterdam may be worth visiting. Receptacles there are port-holes into a much large waste storage dumpster under the ground that is cleared every morning by giant mechanical cleaning machines in a fascinating example of advanced technology for seemingly mundane uses. This applies to recycling as well.

Four pictures I took in Amsterdam of waste collection in 2003

Amsterdam 2003 - - 96-thumb Amsterdam 2003 - - 95-thumb Amsterdam 2003 - - 43-thumb Amsterdam 2003 - - 17-thumb
Pictures of recycling bins in Amsterdam from Pushpullbar forum
Some more pictures here:
Christelle: Another Dutch thing… Garbage!
Christelle: Another Dutch thing… Garbage part 2

a blog about Networks and Places


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