Here are some of the many organizations who are opposed to the construction of the unwanted 710 Freeway extension:

• Advisory Council on Historic Preservation
• Altadena Heritage
• California Office of Historic Preservation
• California Preservation Foundation
• California Public Interest Research Group (CALPIRG)
• California Tax Reform Association
• Caltrans Tenants Association
• Citizens for a Better Environment
• Citizens United to Save South Pasadena
• City of South Pasadena
• Coalition for Clean Air
• Cooperative Resources and Services Project (CRSP)
• ECO-Cities Council
• Eminent Reclaim
• El Sereno Neighborhood Action Committee
• Friends of the Earth
• Green Capitol
• Highland Park Heritage Trust
• Highland Park Neighborhood Association
• L.A. ECO-Village
• Los Angeles Conservancy
• National Alliance of Preservation Commissions
• National Alliance of Statewide Preservation Organizations
• National Parks and Conservancy Association
• Natural Resources Defense Council
• National Trust for Historic Preservation
• National Taxpayers Union
• Neighbors for Better Transportation
• "No 710", Neighborhoods Opposed to the 710 Freeway
• Offices of Antonio Rossman, Counsel for the City of South Pasadena
  
• The Blue Line Construction Authority
• Pasadena Heritage
• Planning and Conservation League Foundation
• Sierra Club
• South Pasadena Chamber of Commerce
• South Pasadena Preservation Foundation
• South Pasadena Unified School District
• Taxpayers for Common Sense