The Renewable Roadsides Act directs the Secretaries of Transportation and Energy to jointly study the potential for developing solar energy generation, storage, and transmission facilities on unused federal land next to highways in the National Highway System. The secretaries must complete their study by December 31, 2025, and submit a comprehensive report to Congress by December 31, 2026, that evaluates which federal lands are suitable for solar development and identifies legal, safety, and policy barriers currently preventing such projects. The report must also recommend ways to streamline development and establish a process for companies and organizations to apply for leases, easements, or joint-use agreements to build and operate solar facilities on these federal roadside properties. This legislation affects the energy sector, transportation infrastructure operators, and solar developers who could potentially use federal lands to expand renewable energy capacity. The bill does not specify funding amounts but establishes clear timelines requiring completion of the study within roughly two years.