To steal a chart from Matt Yglesias, this is a really fascinating chart relating to car usage. Looking at it, there is at best a weak correlation between population density and car usage. To me, what this suggests is that ar usage is largely cultural. In European countries there is an ingrained bias in favor on non-car modes of transportation that just doesn’t exist in the US. In countries like the Netherlands and Denmark that are much more comprehensive public transportation systems available for people to use and a much higher percentage of bike ownership. Those tendencies are at least in part cultural. The other cultural element is development patters. For about 50 years the single family home set off on its own cul-de-sac in its own neighborhood has been a part of the American dream. These neighborhoods have been set of from services much more aggressively than in other countries and development policies have made it actively difficult to not take a large percentage of car trips. This suggests that a sustained effort to incentivize non-car trips could be successful in actually bringing down the number of car trips in the US. If density is not the structural impediment to non-car trips that we thought it was then it could be possible for a state like Virginia to reduce congestion by putting in place serious programs to encourage non-car modes of transportation irrespective of their densities.