A joint agency with a board representing all six Napa County municipalities – the county itself, and its five incorporated cities – the NCTPA operates the VINE bus line, which from its Pearl Street terminal operates routes within and between the cities. The VINE also transports commuters and day trippers between Napa and transportation hubs in El Cerrito del Norte (BART) and Vallejo (Baylink ferry terminal serving San Francisco). The NCTPA manages local paratransit service for riders with special needs, and coordinates spending on streets, roads and bicycle routes throughout the county.
In 2009 the NCTPA's Randolph Street headquarters became the home of the Napa County Arts and Culture Commission, which holds its monthly meetings in the agency's conference room on the first Monday afternoon of each month.