Cars Kill Cities

An interesting article that's being doing the rounds suggests that cars are bad for cities:

In the early 1960s – when highway construction was at its peak and cars were just beginning to leave their mark – a handful of critics predicted there would be irreconcilable tensions between vibrant cities and their motorized inhabitants. Nearly 50 years later, researchers at the University of Pennsylvania published research validating this idea.

The essence of the argument is that cars need places to park.  Space devoted to parking is not devoted to people, in the form of commerce and other sources of employment.  In short, cities should prefer public transit over cars as the primary means of commuting.

The new research offers support for this argument, based on a study of twelve smaller US cities.  At a coarse level, they found a definite inverse correlation between the density of jobs and the fraction of the workforce commuting by car.  A closer examination of six of those cities showed that municipalities that, after 1980, discouraged downtown parking have higher median income and number of jobs.

I haven't read the research paper, only the linked article, so judge my comments accordingly.  Still, while this evidence seems interesting (and supports my biases), there are some definite questions I have.  For one thing, the small sample size makes even the first inverse correlation open to challenges.  Surely it would not have been difficult to gather data for a larger sample set?  Secondly, the direction of causation in the second part of the paper is also unclear; the municipalities which changed to more anti-driving policies were already doing better economically before the change.  These points really need to be addressed in further research before I would feel confident in the researcher's conclusions.