To me, one of the most annoying features of the details of transportation policy is the persistent use of passenger-miles as a denominator in various calculations. As Alon Levy argues this is borderline incoherent and senselessly biased on favor of auto-oriented road projects:

Passenger-miles don’t vote. They’re not a unit of deservedness of subsidy. They’re one unit of transportation consumption. They’re like tons of staple as a unit of food production, or calories as a unit of consumption. We don’t subsidize food based on cents per calorie.

Even as a unit of consumption, there are flaws in passenger-miles as a concept, when it comes to intermodal comparisons. The reason: at equal de facto mobility, transit riders travel shorter distances than drivers. It’s very obvious when comparing total passenger-miles in transit cities and car cities (see e.g. page 36 here). Transit is slower than driving on uncongested roads, but has higher capacity than any road. In addition, transit is at its best at high frequency, which requires high intensity of uses, whereas cars are the opposite. The result is that transit cities are denser than car cities – in other words, need less passenger-miles.

The use of passenger-miles as a unit of measures embeds the assumption that the goal of a regional intra-urban transportation system is to have people traveling as far as possible. Now you could imagine a city in which individuals, firms, structures, natural resources, etc. are just strewn about at random. If that was the case, then you probably would want to organize transportation to maximize distance traveled. People would have arbitrary transportation needs, might need to get very far away, etc. But when you’re talking about a real growing city, a focus on passenger-miles just implies a focus on spreading your urban area out as widely as possible. That’s great if you’re in the business of manufacturing and selling automobiles. And because the US spent decades crafting an industrial policy oriented around the automobile manufacturing and oil extraction industries, we’ve embedded these kind of ideas in a lot of our bureaucratic processes.

Based on the titles, it seems like Charles C Mann wants us to view 1491: New Revelations of the Americas Before Columbus and 1493: Uncovering the New World Columbus Created as a pair. So I read them back to back, and it’s basically true. In principle 1491 is about pre-Columbian America while 1493 is about the Columbian Exchange. In practice, however, in order to understand why it is that the true state of pre-Columbian America hasn’t always been understood, 1491 needs to take us well into the era of colonization, and for 1493 to explain what changed it has to explain what happened before.

As a pair, their fascinating, entertaining, and informative if a bit frustratingly diffuse at times. 1493, in particular, left me eager to learn the answers to some questions that I imagine other readers will have. What did Italians eat before tomatoes? Why does Szechuan cooking have a particular predilection for hot peppers if they’re not even remotely native to the area?

The story of the potato’s introduction into Europe, which he does pursue, is pretty fascinating. Potatoes are a basically optimal source of calories per acre across huge swathes of Northern Europe, but they’re native to Peru. Europeans were extremely reluctant to grow and eat them, but governments wanted to see potato fields planted to increase their population growth rate. Many efforts had to be made to persuade them, and one of Frederick the Great’s many achievements as ruler of Prussia came in this area.

Perhaps the Federal Reserve is like a charging rhino and it’s just very hard to turn it around:

Certainly it’s striking that during the past thirty years of FOMC statements and speeches by chairmen and Fed governors, not a single sentence starts with the clause “as part of our thirty year drive for ever-lower inflation expectations…” even though it’s hard to believe that inflation expectations have been steadily falling for thirty years by accident. Is there some actual reason to be doing this? I feel like if there were, the people doing it wouldn’t be so hesitant to admit that it’s what they’re doing.

It sort of seems like falling communication costs should reduce the need for people to crowd together, so I can see why people say things like this:

With broadband, employees no longer need to physically be transported to work. He sees Americans moving to scenic, ideal locations such as the mountains of Montana or the hills of Santa Fe. [Joel] Garreau splits his time between Fauquier County and Arizona.

“What you’re seeing now is what I call the Santa Fe-ing of the world, or the Santa Fe-ing of America,” he said. “The fastest growth you’re seeing is in small urban areas in beautiful places, because now you’ve got e-mail and Web and laptops and iPhones and all that jazz.”

That’s not an insane piece of idle speculation, but like David Frum I don’t understand how it survives contact with an effort to look up actual population growth figures. People are moving in droves to the Houston and Dallas metropolitan areas, neither of which are small or idyllic. Meanwhile, it’s hardly like the invention of the Internet has made it super-cheap to buy a house in Silicon Valley. Quite the reverse, actually. Most of the larger northeastern cities have seen substantial revitalizations of their downtown areas over the past twenty years, and the growth in sunbelt cities has tended to take big cities like Phoenix and make them bigger.

There are two kinds of reasons for this.

One is that online and offline communications aren’t identical. They seem in many ways to be complements rather than supplements. A non-economic way to think about this is that in principle thanks to the Internet I could spend less time socializing with people face-to-face than a past person would do. In practice, that’s not what happens. Organizing face-to-face socializing is one of the primary things I use modern information technology to do. The web has also given me a vast and far-flung network of readers, acquaintances, and contacts who I socialize with face to face from time to time as happenstance puts us in the same city. The Web doesn’t crowd out real life, it enables it. By the same token, it would be wrong to say that the allows ThinkProgress to get away without meetings or in-person interaction. Rather, without the Internet, we wouldn’t have jobs and there’d be nothing for us to hold meetings about.

The other is that lots of services can’t be provided over the internet. The web can’t cut your hair, do your nails, cook you dinner, clean your teeth, operate on your injured wrist, redo your floors, etc. You can of course get these services in small towns if you want. But large cities have more choices, more specialization, more competition, etc.