A Two-Dimensional Screening Framework for Compact City Plans: Spatial Reorganization Burden and Service-Access Mobility-Energy Outcomes

Japan’s Location Optimization Plans designate Residential and Urban Function Guidance Zones, but their outcomes for non-commuting, non-school access to daily services are rarely screened against the spatial reorganization they require. This study pairs the Urban Spatial Reorganization Distance (USRD), an exact optimal-transport, latent-demand-weighted measure of minimum reorganization, with the Urban Mobility Efficiency Index (UMEI), a demand-based measure of mobility energy normalized by the 2020 Census municipal population. Across 305 municipalities, median exact USRD was 2.45 km; 205 (67.2%) improved under full realization with a fixed transit network, whereas 100 (32.8%) did not. Total USRD was not monotonically associated with UMEI improvement (Spearman ρ=−0.056, p=0.331), but non-improvement was concentrated in designated and core cities and accompanied by lengthened modeled trips. Compactness can therefore worsen service-access efficiency when residential and destination zones are spatially misaligned. The USRD–ΔUMEI matrix is a screening framework, not an estimate of financial implementation cost.