Randall Crane’s Urban Planning Research discusses accessibility vs. mobility. He seems to be searching for a definition.
Accessibility is nicely defined as the ease of reaching particular destinations. That can be operationalized (and easily communicated) as how much stuff you can get to in a particular amount of time (e.g. number of jobs within 20 minutes). Our book from the conference is now out. The first of many reports on methods for measuring accessibility will be out soon.
Randall rightly notes that the importance of different things varies for different people. Accessibility measured as above is clearly a supply (or opportunities) measure, and makes no account of demand. No one measure encapsulates the entire economy.
Choices have costs. Increasing acccessibility is not free. Enabling someone to access 101 grocery stores in 30 minutes travel by auto instead of 100 will likely not be noticed unless that grocery is somehow distinct, and valuable, to an individual consumer.
— dml
Day: 2006-05-11
“Data” is not the plural of anecdote
In the blog L.A. traffic sucks: Let’s fix it! the author argues that driving is an “addiction”. I believe people are behaving individually rationally (with perhaps irrational preferences) to achieve personal satisfaction, which may result in societally unoptimal outcomes.
The value of smooth roads
From today’s Star Tribune: State of our roads is getting bumpier
The article says “Department officials say they don’t consider the condition of the roads a safety concern,” and there is no evidence unsmooth roads (at least in the range considered in Minnesota, where roads are much better than, say, Africa), reduce capacity, so what is the rationale for smooth roads?
The answer seems to be to prevent future deterioration.
“”You can reconstruct the roads already in poor condition or you can keep the roads that are about to go into the poor category from ever getting there by doing something first,” Janisch said. “It’s cheaper to keep them up.””
But is there a value to smooth roads? How much of a premium would travelers pay, all else equal, to have a smoother ride?
— dml
Highways in Africa
In the most recent episode of The West Wing(the penultimate episode “Institutional Memory”), White House Chief of Staff C.J. Cregg is being recruited to help run a foundation loosely based on the Bill and Melinda Gates Foundation, and her idea of what the best use of $10 billion would be to criss-cross Africa with highways, which would enable the delivery of medicine, expand trade, and do all sorts of good things.
David Levinson, Transportist 