Bay Area Rapid Transit District
Fares on BART are comparable to those of commuter rail systems and are higher than those of most subways, especially for long trips. The fare is based on a formula that takes into account both the length of the trip and the counties passed through. A surcharge is added for trips traveling through the Transbay Tube, to Oakland International Airport, to San Francisco International Airport, and/or through San Mateo County, a county that is not a member of the San Francisco Bay Area Rapid Transit District.