Impact Sciences is preparing a Program Environmental Impact Report (PEIR) for the 2020-2045 Regional Transportation Plan /Sustainable Communities Strategy (2020 RTP/SCS) for the Southern California Association of Governments (SCAG). The programmatic environmental analysis for the 2020 RTP PEIR evaluates potential environmental effects consisting of direct and indirect effects, growth-inducing impacts, and cumulative impacts, and will include mitigation measures to offset any identified potentially significant adverse environmental effects. In addition, the PEIR will be available to act as the foundation for subsequent, site-specific environmental review documents (including Addendums, Supplemental EIRs, Subsequent EIRs) in jurisdictions throughout the region that will be conducted by implementation agencies, as transportation and development projects in the Plan are implemented (State CEQA Guidelines Sec. 15385). In addition to fulfilling legal requirements, the PEIR provides an opportunity to inform decision makers and the public about potential environmental effects associated with the implementation of the RTP and alternatives. This first-tier regional-scale environmental analysis will also help local agencies evaluate and reduce direct and indirect impacts, growth-inducing impacts, and cumulative environmental effects with respect to local projects.