The Port Optimization for Responsible Transportation Act directs the Secretary of Transportation to streamline environmental review processes for port projects by allowing the Maritime Administration to adopt categorical exclusions already used by highway, transit, and railroad agencies, and to create new port-specific categorical exclusions within six months of enactment. The bill affects port authorities receiving federal grants by establishing timelines to update categorical exclusions every four years, extending grant application deadlines when solicitations are amended, and requiring faster approval of minor project budget adjustments. Additional provisions exempt port authority projects from certain federal permitting oversight requirements and require the Secretary to provide detailed certifications when denying waivers for American-made equipment requirements, including lists of domestic manufacturers. The legislation also includes a congressional sense supporting group purchasing arrangements among port authorities to build domestic manufacturing capabilities. No specific new funding is appropriated in the bill, which focuses on administrative efficiency and regulatory changes affecting existing Maritime Administration grant programs.