TSTC was launched in the early 1990s by a dozen New York, New Jersey, and Connecticut environmental and planning organizations that were alarmed by the mobility, economic, quality of life and environmental implications of worsening auto and truck dependence in the metropolitan area, and believed that the 1991 ISTEA federal transportation legislation created new opportunities to advocate for sustainable state transportation policy.

TSTC seeks to convince policymakers to maintain and increase subsidies for mass transit operations and construction projects.

Working with groups in the South Bronx, TSTC succeeded in inserting plans for removing the Sheridan Expressway into New York State Department of Transportation studies for the area.

The New Jersey DOT is adopting transportation-efficient land use planning, which seeks to reduce the heavy car trip generation that characterizes sprawl development.

In Connecticut, a state without tolls, TSTC is pushing for congestion pricing as a way to manage traffic and pay for transportation projects.

In Long Island, Tri-State worked with civic groups to provide support for bus riders calling for adequate funding and reliable service.

TSTC advocated for local Complete Streets policies throughout New Jersey: Cranford, Newark, Trenton, Fanwood, Linden, Mantua Township, Camden, and Woodbury.

TSTC's advocacy contributed to half of the Smart Growth America's top eight NJ Complete Streets policies in 2013 [Trenton, Linden, Camden, and Cranford].