In a little over a decade, traffic calming in the United States has expanded from a few scattered programs, with limited scopes and toolboxes, to a mainstream activity of transportation planning. A comparative case study design was used to study 10 early adopters of traffic calming. judged against six traffic calming policies, none of the US programs surveyed has transitioned to a European emphasis on the needs of pedestrians and bicyclists, thereby contributing more directly to the public goals of congestion management, active living, and air quality. However, programs in case study jurisdictions known for their progressive planning cultures have made some progress in this direction.