Transportation Development Act (TDA)

SJCOG is responsible for the apportionment of Transportation Development Act (TDA) funds each year in conformance with legislative priorities. TDA funds include the Local Transportation Fund and the State Transit Assistance Fund.

The TDA has long been a cornerstone of state transit funding. This state law allows each county to establish a quarter-cent sales tax to finance a wide variety of transportation projects, including:

  • Transit operations
  • Bus and rail projects
  • Special transit services for disabled riders
  • Pedestrian and bicycle facilities
  • Transportation planning.

State Transit Assistance

State Transit Assistance (STA) funds are generated by the sales tax on diesel fuel, and the amount of money available for transit agencies varies from year to year based on the ups and downs of diesel prices. The State splits the STA program into two components:

  • Population-based funds: SJCOG receives STA based on our share of the population. SJCOG determines how to use these funds
  • Revenue-based funds: The State allocates funds to transit operators based on their revenue as defined by PUC 99314 (b).

Operators have full discretion over the use of TDA and most of STA apportioned to them. Funds may be used by transit operators for both capital projects and transit operations. For most smaller transit agencies, TDA and STA are their main sources of operating funds.


The transit operators and other member agencies in the San Joaquin region submit their annual TDA claims based on these apportionments and in compliance with SJCOG TDA Administration Policy.  SJCOG is subsequently required by state law to prepare and submit an audit of its performance on a triennial basis to the California Department of Transportation (Caltrans) in order to continue receiving TDA funding.