John Semmens over at Transportation Research Digest flagged this study of Smart Growth’s potential transportation impacts in two small towns in Maine. The study is useful because it provides a glimpse into how Smart Growth–high density, mixed-use development–might be applied outside large urban areas like Washington, D.C., Chicago, San Francisco, etc.
The estimates were performed by the University of Vermont’s Transportation Research Center for the towns of Lisbon (population 9,100) and Sanford (population 20,800). The study used transportation demand and land use modeling through the year 2030 based on two scenarios for each town: directing future development into one mixed use development or developing future development into two mixed used developments in Lisbon and three in Sanford. (Yes, these are small towns, so future growth in a state that isn’t growing very much doesn’t generate much of a change in actual land use.)
In the Lisbon case, about a quarter of projected future growth would be directed into Smart Growth areas under scenario one. In Sanford, about 20 percent of future growth would be directed into these areas. Under the second scenario, about 60 percent of the population and 41 percent of the jobs would be directed into the Smart Growth areas in Lisbon, and about half the population and one third the jobs in Sanford would go into these areas.
The results weren’t too surprising: the effects of Smart Growth would be small. According to the executive summary:
“In Lisbon, VMT and GHG emissions estimated for the Targeted Smart Growth scenario were
0.43% and 0.42% lower, respectively, than estimates for the Status Quo scenario. The VMT
percent reduction corresponds to 656 fewer vehicle miles traveled daily in the Town of
Lisbon. Under the Multiple Smart Growth scenario, the reduction in network-wide VMT and
GHG emissions was approximately 0.68% and 0.57%, respectively, compared to Status Quo.
The VMT percent reduction corresponds to 1,038 fewer vehicle miles traveled daily.
Modeling the Transportation Impacts of Smart Growth Development in Maine
“In Sanford, VMT and GHG emissions estimated for the Targeted Smart Growth scenario
dropped by 0.24% and 0.27%, respectively, from the Status Quo scenario. The VMT percent
reduction corresponds to 985 fewer vehicle miles traveled daily in the Town of Sanford.
Under the Multiple Smart Growth scenario, the reduction in network-wide VMT and GHG
emissions was approximately 0.42% and 0.43%, respectively, compared to Status Quo. The
VMT percent reduction corresponds to 1,698 fewer vehicle miles traveled daily.”
But, here’s the kicker from my view. In order to get these small impacts, the towns had to impose an enforceable growth boundary so that land would, in effect, be rigged to develop at higher densities. Second, the modeling assumed that new growth would be directed into these mixed use, Smart Growth areas. The modelers redirect the development that would have gone outside the growth boundary into the the Smart Growth developments.
Here’s the question: What mechanism would accomplish this? Presumably, zoning and land-use regulation would effectively limit the amount of housing that could be built outside the designated Smart Growth areas so vacant land inside the growth boundary couldn’t be used to accomodate the new development.
Moreover, this implies a substantial housing preference mismatch: households that preferred the low-density development outside the growth boundary are now forced to choose higher-density housing designated by town planners.
The provocative part of the analysis is that it really justifies the worst fears of critics of Smart Growth: top down central planning is directing housing choice regardless of the preferences for households. Smart Growth advocates often claim their goal is only to provide choices in the market place. In high-growth, built up areas, this is a valid perspective, and we welcome ways to free up the housing market (Houston style) to allow real-estate markets to meet this demand.
In slower growth, small town areas, however, coercion is fundamental to meeting Smart Growth goals. Smart Growth isn’t about choice any more than Portland’s growth policies are about choice. Smart Growth policies are about scripting an urban landscape that is different from what households freely choose in the market place.