The Mother Nature Network has a slideshow up showing seven car-free cities around the world. What’s interesting is that the majority are tiny islands and heavily reliant on the tourist industry. The largest “city,” Venice, is just a lot of tiny islands heavily reliant on the tourist industry.

The slideshow implicitly raises the question of what it would require to go totally car-free. As sustainable transportation advocates know, you don’t need a car to get around a dense city. Whether through transit or walking and cycling, it’s not strictly necessary (although it is often more convenient). The place where automobiles become truly necessary is when you want to travel between rather than within a metropolis.

The image of the car-free island is a very good one.

While MNN’s car-free places mostly don’t even have the population size to have density, compare those images to MWCOG’s image of where people who work in the D.C. CBD live:

The resemblance to an island is striking.

A look at the history of transportation will provide a similar point of view. The earliest cars in America weren’t used for daily urban transport; they were used for touring and for traveling, or for ostentatious displays of wealth. The car took us off our urban islands, not across them.

Personally, I had access to a car in D.C. for about a month and used it three times. I went to Annenberg, VA for Korean food, to Harper’s Ferry to go hiking, and to pick someone up from the Poconos. I only drove when I had to leave the urban island and absolutely never otherwise and thereby got the biggest benefit of automobility without incurring too many of the social costs.

In terms of policy, this should help us conceptualize just what cars are and aren’t good for. For a while I’ve been toying with the idea there should be parking rates that specifically encourage you not to move your car, pushing you to use it for the kinds of outward trips that only cars can take but disincentivizing daily use. You could do this with a flat fee for each time you park, or with very high rates for the first half-hour and a normal gradation after that. Returning to my experience this summer, I would have driven more had I had easy access to the car. It was parked about twenty minutes from where I’m living, so there was a distinct per trip, rather than per mile, cost to driving.

We don’t need to go car-free. We should not go car-free; we would lose so much access to so many important things. But looking at those few places that are entirely car-free does provide an important look at precisely why cars are so necessary. MNN’s car-free islands can be completely car-free because there’s no way to leave the island by car anyway. The place where cars outcompete other modes the most is taken away. To reduce driving without eliminating the real accessibility benefits of driving, we should try to create policies that help make our cities act more like islands, with cars (and rail and air and ships) creating outward interconnectivity but becoming less and less necessary internally.