The street level built environment and physical activity and walking: Results of a predictive validity study for the Irvine Minnesota Inventory

The Irvine Minnesota Inventory (IMI) was designed to measure environmental features that may be associated with physical activity and particularly walking. This study assesses how well the IMI predicts physical activity and walking behavior and develops shortened, validated audit tools. A version of the IMI was used in the Twin Cities Walking Study, a research project measuring how density, street pattern, mixed use, pedestrian infrastructure, and a variety of social and economic factors affect walking. Both bivariate and multivariate analyses were used to assess the predictive value of the IMI. We find that while this inventory provides reliable measurement of urban design features, only some of these features present associations with increased or decreased walking. This article presents two versions of shortened scales—a prudent scale, requiring association with two separate measures of a physical activity or walking behavior, and a moderate scale, requiring association with one measure of physical activity or walking. The shortened scales provide built environment audit instruments that have been tested both for inter-rater reliability and for associations with physical activity and walking. The results are also useful in showing which built environment variables are more reliably associated with walking for travel—characteristics of the sidewalk infrastructure, street crossings and traffic speeds, and land use are more strongly associated with walking for travel, while factors that measure aesthetics are typically less strongly associated with walking for travel.