Both Ian and Graydon have talked about the matter of cars and suburbia. I am not an expert in urban philosophy, but I might risk one small insight.
Both gentleman have expressed fondness for public transit, preferring to ride a bus instead of a car, though in a different way. Graydon thinks cars isolate people from their surroundings by glass and velocity. Ian finds a little familiar society on buses.
To me, the urban social contact found while walking along on a street, or riding along in a bus, is not substantial. There is only potential interaction. In a crowded downtown as in a crowded bus, people will just be passing through to their real destination, while being metaphorically or actually enclosed together. The group that forms from such incidental co-enclosure is not a miniscule family to gather comfort from – it is just a mellowed-out mob of anonymous passerbys.
My current favorite objection to mass transit is the self-disempowerment that this entails. A passenger relinquishes direct control over one’s travels, the safety of one’s person, and hands it to the driver/pilot. He surrenders his preferences to the logistic constraints involved in serving the aggregate demand. It is a little like going to a supermarket to pick from a standard menu of mass-produced food. He is depending on the system.
Driving is a little like farming in terms of being the reward and burden of individual effort. They still depend on infrastructure (fuel, roads, maintenance), but these are less immediate, more easily substituted by one’s own efforts. They cut a tangible umbilical cord between the individual and the impersonal society at large. I like that.