The "21st Century ROAD to Housing Act" seeks to address housing supply and affordability challenges through comprehensive legislative changes across multiple federal agencies and programs. The bill proposes significant reforms to housing counseling, environmental review processes, and the Federal Housing Administration (FHA) to facilitate housing development and access. Title I, "Opportunities for Housing," introduces federal guidelines for point-access block buildings and exempts certain infill residential housing from environmental review requirements. It also establishes an FHA Pilot Program to increase access to small-dollar mortgages and a temperature sensor pilot for federally assisted rental units. Furthermore, it mandates HUD guidelines for state and local zoning frameworks to promote housing production and abolishes the Regulatory Barriers Clearinghouse. Title II, "Building More in America," focuses on increasing housing supply by prioritizing HUD grants in opportunity zones and establishing a "Whole-Home Repairs Act" to provide grants and forgivable loans for home repairs. It expands eligible activities for Community Development Block Grants to include new affordable housing construction and streamlines environmental reviews for various HUD housing activities, particularly for infill projects. This title also creates an Innovation Fund to reward localities that increase housing supply and an "Accelerating Home Building Act" to support the use of prereviewed designs for mixed-income housing. The "RESIDE Act" establishes a pilot program to convert vacant commercial buildings into attainable housing, while the "Housing Affordability Act" adjusts FHA mortgage limits to reflect current construction costs. Title III, "Manufactured Housing for America," modernizes the definition of manufactured homes to include those without a permanent chassis and grants HUD primary authority for construction and safety standards. It also directs FHA to review barriers to modular home financing and increases loan limits for property improvements and manufactured homes under FHA Title I. Title IV, "Accessing the American Dream," addresses small-dollar mortgages by requiring reports on loan originator compensation and evaluating the impact of points and fees. The "Appraisal Industry Improvement Act" streamlines appraiser certification, establishes a national registry for trainee appraisers, and provides grants for workforce development. It also creates an Escrow Expansion Pilot Program for HUD-assisted families and streamlines inspection requirements for Section 8 housing vouchers. Title V, "Program Reform," reauthorizes the HOME Investment Partnerships Program, adjusting income limits and allowing funds for infrastructure improvements in nonentitlement areas. The "Rural Housing Service Reform Act" applies multifamily mortgage foreclosure procedures to USDA loans, preserves rental assistance contracts, and establishes a permanent Housing Preservation and Revitalization Program. It also includes provisions for staffing and IT upgrades within the Rural Housing Service. Title X, "Home-Ownership for Main Street America," enacts the "Homes Are for People, Not Corporations" provision, which prohibits large institutional investors from purchasing single-family homes, with specific exceptions. This title also establishes a renter outreach resource and imposes civil penalties for violations, with funds directed to the HOME Investment Partnerships program for homeownership expansion. Finally, Title XI, "Central Bank Digital Currency," prohibits the Federal Reserve from issuing a central bank digital currency without explicit Congressional authorization, with an exception for open, permissionless, and privacy-preserving digital assets.