From Policy Authorization to Practical Execution: A Decision-Support Framework for Implementing Housing Supply Strategies in the United States

Accessory Dwelling Units (ADUs) have been widely promoted across the United States as a policy mechanism to address housing shortages by expanding housing supply within existing residential neighborhoods. Despite broad legislative support, the actual implementation of ADU policies remains inconsistent and limited across jurisdictions. This paper examines the structural factors contributing to the gap between policy authorization and real-world execution, with particular attention to early-stage uncertainty, fragmented zoning and permitting frameworks, and the absence of systematic feasibility assessment mechanisms. Drawing on policy analysis and observed implementation patterns in high-density urban contexts, the study argues that ADU underperformance is primarily an execution challenge rather than a limitation of design capability or construction technology. By reframing ADU deployment as a housing policy execution problem, this research highlights the need for upstream decision infrastructure to improve predictability, reduce administrative friction, and enable more equitable access to small-scale housing supply expansion. This decision-support approach operates prior to architectural design, engineering documentation, and formal permitting submissions, and does not replace licensed professional services or governmental review.