The Contra Costa Transportation Authority (CCTA) was originally formed to manage the funds generated by the half-cent transportation sales tax which Contra Costa County voters enacted in 1988, and to oversee the implementation of the Measure C Expenditure Plan.

In 2004, the sales tax was renewed for an additional 25 years (beginning on April 1, 2009, through 2034), and a new expenditure plan, the Measure J Expenditure Plan was adopted. As Contra Costa County's transportation sales tax agency, CCTA oversees the design and construction of the transportation projects included in the Expenditure Plans, carries out the programs included in the Expenditure Plans, most notably, the county's Growth Management Program (GMP), and provides the financial structure that ensures the optimum use of the sales tax dollars as intended by the voters.

In 1990, CCTA took on the role of Contra Costa County's Congestion Management Agency (CMA). In that capacity, the Authority is the primary transportation planning agency for Contra Costa County, responsible for prioritizing our county's share of available federal, State and regional transportation funds. As the CMA, CCTA prepares the county's Congestion Management Program (CMP), monitors levels of service on the county's roadways and works with other CMAs and agencies to address regional issues. The most recent CMP was adopted in 2009.

In 1992, CCTA was designated Contra Costa's Program Manager for the return-to-source portion of the regional Transportation Fund for Clean Air (TFCA). In this capacity, CCTA is responsible for the allocation of approximately $1.3 million dollars annually for projects that reduce air pollution caused by motor vehicles.