This study focuses on developing an urban design audit tool to evaluate features in the built environment that may encourage or discourage physical activity. The audit instrument divides the features into four categories: accessibility, pleasureability, perceived traffic, and crime safety. For example, under pleasureability, the tool allows auditors to quantify, on a scale of 1-3, whether the appearances of buildings on a block are visually compatible. This variable will allow researchers to test the idea that compatible architecture creates an environment that encourages more walking. The researchers are asking three diverse focus groups of ordinary people to help generate items to include in the tool, and are asking for feedback from a panel of experts on physical activity and design. The tool allows block-by-block evaluation of the environment and can be used in many different types of places including urban, suburban, small town, and rural settings. The Boarnet/Day team is using three observers, working separately, to test the instrument in 20 different settings around Southern California. The audit tool should allow future researchers to conduct straightforward data collection and analysis as they evaluate the built environment.