The San Mateo County Transit District is the administrative body for the principal public transit and transportation programs in San Mateo County: SamTrans bus service including Redi-Wheels and RediCoast paratransit service, Caltrain commuter rail and the San Mateo County Transportation Authority. Caltrain and the TA have contracted with the District to serve as their managing agency, under the direction of their independent board of directors.

The Transit District employs approximately 670 people, most of whom divide their time between SamTrans, the San Mateo County Transportation Authority and Caltrain. While the train engineers don't drive buses, or vice versa, the same administrative employees who pay the bills, answer the telephones in the Customer Service Center, plan new services and programs, hire new employees, and perform all other administrative tasks, spend a portion of their time working for Caltrain and the TA.

This consolidation of administrative functions helps reduce costs and maximize efficiency. By using the same administrative employees to manage the work of three transportation agencies, the Transit District is able to keep administrative costs low, while delivering a wide range of high-quality transportation services.