Richard White, the longest-serving general manager for the Washington Metropolitan Area Transit Authority (WMATA), is stepping down from his position early this year. Dan Tangherlini, director of the District of Columbia's Department of Transportation, will serve as acting general manager until a permanent replacement is hired. White, who will continue in his position during the transition period, is credited with helping to stabilize the region's bus service and overseeing the system's first significant rail expansion. He also helped to bolster the transit system's security preparedness in the wake of the 9/11 terrorist attacks. White was appointed WMATA's general manager and chief executive in 1996. He recently served as chair of the American Public Transportation Association's Executive Committee.