The STA is primarily responsible for administering the Measure A program: the half-percent sales tax for transportation improvements in Sacramento County.

The STA also administers the Sacramento Metropolitan Freeway Service Patrol (FSP) program in cooperation with Caltrans and the California Highway Patrol. The program's primary objective is to reduce the traffic congestion caused by roadway incidents.

The STA Governing Board and staff also serve as the Governing Board and staff of the Sacramento Abandoned Vehicle Service Authority (SAVSA). SAVSA provides funding to participating local jurisdictions for the abatement of abandoned vehicles and vehicle parts on streets and private property.

The STA is the only local countywide transportation agency and, therefore, provides a number of other functions related to setting priorities for the expenditure of specified state and federal transportation funds in Sacramento County.