bypass study
Paul,
When I was at U. of Texas I worked on a study looking at exactly this issue. There are a couple of things to consider:
Is the community suburban, ex-urban, or rural?
How geographically isolated is it? Are there towns on the same highway which are relatively close and close to the same size?
Is there an activity generator downtown (i.e. a courthouse)?
What is the current composition of downtown businesses?
What is the population (the smaller the town, the larger the impact)?
What is the current traffic flow?
Is the land around the bypass incorporated? What are the cities plans to extend utilities? What is the area around the bypass zoned?
There are a ton of other things. Here are the citations for the project I worked on:
Handy, S.L., S. Kubly, J. Jarrett, and S. Srinivasan. Economic Effects of Highway relief Roues on Small and Medium-Size Communities: Literature Review and Identification of Issues. Report 0-1843-1, Center for Transportation Research, for the Texas Department of Transportation, April 2000.
Handy, S.L., S. Kubly, D. Larsen, and M. Oden. Economic Impacts of Highway relief Roues on Small and Medium-Size Communities: Case Studies. Report 0-1843-3, Center for Transportation Research, for the Texas Department of Transportation, March 2001.
Kockelman, K., S. Srinivasan, and Handy, S.L.. Economic Effects of Highway relief Roues on Small and Medium-Size Communities: An Econometric Analysis. Report 0-1843-2, Center for Transportation Research, for the Texas Department of Transportation, Revised May 2001.