It’s well established that people living in urban areas use cars less frequently than their suburban and rural counterparts. Some argue that it is thanks to better transit services that urbanites don’t drive but there is another reason for success. Population density alone can make a striking impact on how often people drive!
Holtzclaw concluded that even in areas with minimal transit service, density affected VMT [vehicle miles travelled]. For example, in an area with only two buses per hour, a census tract with 20 households per acre drove about 40 percent less per household than one with two units per acre (15,374 per year as opposed to 27,339). But VMT did not stop dropping at the 20 households per acre level. An area with 100 households per acre drove 1/3 fewer miles than the 20-per-acre neighborhood (10,028 VMT per household) and one with 500 households per acre drove 40 percent less than the area witih 100 households per acre (5781).