Tilly Chang serves as the Executive Director at the San Francisco County Transportation Authority. The Transportation Authority administers Prop K, the city’s half-cent transportation sales tax program as well as the Prop AA vehicle registration fee. The agency also serves as the county-wide Congestion Management Agency which coordinates funding and transportation investment for San Francisco’s multi-modal transportation system. The agency is governed by the 11 members of the Board of Supervisors, acting as the Transporation Authority Board of Commissioners.