This bill streamlines the environmental review process for public transit projects by allowing larger transit agencies to take over certain responsibilities currently handled by the federal government. Specifically, it lets transit agencies in urbanized areas with populations over 200,000 that have adequate legal and financial capacity make decisions about whether transit projects qualify as "categorical exclusions" under environmental law—meaning they don't require full environmental impact assessments. Transit agencies assuming these responsibilities would operate under memoranda of understanding with the federal government lasting up to three years (or five years for agencies with 10+ years of experience), would be solely liable for compliance with applicable federal laws, and could use transit funding to pay for attorney's fees related to these reviews. The bill preserves the federal government's oversight role and allows agencies to terminate these arrangements with 90 days' notice, while the federal government can terminate if an agency fails to comply after a 120-day correction period.