An examination of access to walkable neighborhoods in the las vegas metropolitan area

Background: Walkability measures often include some metric of street connectivity, land use mix, and residential density. The urban design of the southwest and many newer cities is different in a way that may result in an over estimation of street connectivity. Southwest cities were designed with residential areas which are separate from all other uses. These areas are often within a single entry community (SEC) in which there is only one entrance (gated or un-gated) with the perimeter surrounded by block walls. This design makes direct walking routes nearly impossible. Measuring street connectivity without taking this design feature into consideration would result in an over estimation of walkability. This purpose of this study was to determine if accounting for SECs resulted in a significant difference in overall walkability scores. Methods: 20 geographically different Las Vegas census block groups were chosen and the number of true intersections measured in ArcGIS using methods developed by Frank et al. (2010). The same neighborhoods were then assessed for the presence of SECs using ArcGIS imagery and Google maps. Intersections inside SECs were then removed. A paired t test was used to assess the mean difference of intersection density before and after adjustment. Results: There was a statistically significant decrease in the number of true intersections after the adjustment (before M=57.8; after M=45.7). The eta squared statistic indicates a large effect size (0.3). Conclusions: The urban design of much of the southwest is unique and must be considered when measuring and attempting to increase walkability.