Examining the background characteristics of people and their choices of transportation for the journey to work, the researchers not surprisingly confirm that those with higher incomes who own automobiles are less likely to use public transit than those with lower incomes who do not own cars.
This is maybe a little exaggerated, but only a little. While this type of analysis is probably important in a regional planning context (the magnitudes of those coefficients are important, after all) it's less clear why these studies are still being undertaken in an academic one. One explanation is that they're easy (relatively) to complete and they're still sexy to publish. Especially if one of the coefficients has a counterintuitve sign or magnitude but is readily interpretable because of the particulars of the dataset.
Research on these spatial, economic, and population correlates of transportation fails to explain how they evolved.
Indeed, it seems as though transportation studies is always starting from scratch or stating the obvious. Worse, it takes a thoroughly positivist and technological deterministic stance: if the right technology is provided in the right conditions then it will diffuse and transport will be sustainable. Many of my colleagues devote substantial amounts of time to studying (e.g.) the optimum location of alt-fuel refueling infrastructure. No one to my knowledge is putting this type of analyses together (well) with how transportation systems have evolved in the past (in a society, in a culture, in a political system) and how this is likely to connect to the future. weaving together technology, culture, politics, to determine sustainable futures is likely to yield better results than analyses which cut out any single portion. yago knew this in 1983. howcome we don't know it now?
Yago, G. (1983). "The Sociology of Transportation." Annual Review of Sociology 9: 171-190.