A post over at The Third Rail wondered what it would take to get people out of their cars (specifically, into transit). On a mostly parallel idea, I found a paper (long) that talks about land use changes in some Austin neighborhoods that might or might not get people to walk more.

First, certain urban form characteristics which planners can encourage through land use policies and design guidelines make walking and shopping locally more attractive choices. The most important policy is to encourage commercial activity within walking distance of residential areas - a necessary but not sufficient condition for walking. ... These policies will not mean a significant reduction in automobile travel, but they will mean that the choice to walk or shop locally becomes more competitive with driving to more distant locations.

Second, most of what influences residents' choices about walking and local shopping is not anything that planners can do anything about. The fact that residents have so many choices -- not just the local supermarket but also the next one down the road or the health food store across town -- means that few of them will always choose the closest option, instead sometimes or always traveling farther to find the store that better meets their needs. ...Many of the characteristics that produce a comfortable and interesting walking environment depend not on neighborhood design but on how residents adapt and adapt to the neighborhood... The connection residents feel to their local businesses depends on the efforts those businesses make to foster those connections.

So can land use policies be an effective strategy for reducing automobile dependence? Yes and no. Land use policies are clearly important in determining whether residents have the choice to do something other than drive. In that sense they help to reduce the need to drive. But simply having an alternative to driving doesn't mean that residents will take advantage of it. This study shows that some people are more disposed to walk than others and that those who are more disposed to walk are more disposed to chose a neighborhood where walking is an option. ... Planners should focus on land use policies that will help to provide alternatives to driving, but they shouldn't expect such policies alone to control growing levels of travel.