The Dumbarton Express bus service connects areas of Alameda, San Mateo, and Santa Clara counties via the Dumbarton Bridge. AC Transit administers the service and the Dumbarton Bridge Regional Operations Consortium provides oversight. Funding was previously split between consortium members but is now provided by $2.2 million in regional funds. The service operates on two routes with frequencies of every 30-45 minutes. Ridership has increased to nearly 1,200 daily passengers following service enhancements including increased frequency, extended hours and routes, and marketing initiatives.