1. Semra A. Aytur, MPH, PhD; Kelly R. Evenson, MS, PhD; and Wayne D. Rosamond, PhD, are with the Department of Epidemiology, School of Public Health, University of North Carolina at Chapel Hill. Daniel A. Rodriguez, MS, PhD, is with the Department of City and Regional Planning, University of North Carolina at Chapel Hill. Diane J. Catellier, DrPH, is with the Department of Biostatistics, Collaborative Studies Coordinating Center, University of North Carolina at Chapel Hill