Taxis in the Sky

From The Atlantic by James Fallows: Taxis in the Sky about the emerging market for air taxis connecting smaller cities not served by point-to-point service.
“Herriott and Sawhill have developed a model to simulate the individual decisions that go into every one of these business trips. The model starts with the likelihood that a person in any one city, let’s say Mobile, will want to go to another, say Savannah, on any given weekday (for now, DayJet is a weekday-only service). These predictions are based on average income in each city, business relations, and other factors, and are constantly tuned to reflect real data. “It’s like the pull between two planetary bodies,? Herriott said. “Almost a Newtonian law!? (He was joking.)”
Could they be using a version of The Gravity Model, which implements a version of Tobler’s First Law of Geography “Everything is related to everything else, but near things are more related than distant things.”

Can better highways save Afghanistan?

From The Atlantic, an interesting article by Philip Smucker: Asphalt Dreams about the correlation between development highways and stability in Afghanistan. The article reminds that highways are not just for moving troops quickly to deploy elsewhere, but also to help settle the places they run through. While that may not have been foremost on the mind of proponents of The Dwight D. Eisenhower National System of Interstate and Defense Highways, (even though it has Defense in its name) it certainly has been important throughout history.

ICFTI 3

UPDATED August 27, 2009.
I am leaving today for Paris, where I will be presenting a paper at The 3rd International Conference on Funding Transport Infrastructure. We hope to have the 4th conference in Minnesota next summer.
The paper is:
Levinson, David and Andrew Odlyzko (2008) Too Expensive to Meter: The influence of transaction costs in transportation and communication. Philosophical Transactions of the Royal Society A: Mathematical Physical and Engineering Sciences 366(1872) pp 2033-2046 [doi]

Abstract. Technology appears to be making fine-scale charging (as in tolls on roads that depend on time of day or even on current and anticipated levels of congestion) increasingly feasible. And such charging appears to be increasingly desirable, as traffic on roads continues to grow, and costs and public opposition limit new construction. Similar incentives towards fine-scale charging also appear to be operating in communications and other areas, such as electricity usage. Standard economic theory supports such measures, and technology is being developed and deployed to implement them. But their spread is not very rapid, and prospects for the future are uncertain. This paper presents a collection of sketches, some from ancient history, some from current developments, that illustrate the costs that charging imposes. Some of those costs are explicit (in terms of the monetary costs to users, and the costs of implementing the charging mechanisms). Others are implicit, such as the time or the mental processing costs of users. These argue that the case for fine-scale charging is not unambiguous, and that in many cases may be inappropriate.