A Mobility Priority Index for Data-Driven National Bridge Preservation Prioritization

Bridge and pavement management systems typically evaluate structural condition and roadway performance separately, limiting network-level consideration of infrastructure condition and traffic exposure. This study develops the Mobility Priority Index (MPI), a relative composite screening measure that integrates pavement roughness, bridge deck condition, current traffic exposure, and projected traffic growth. A transparent and transferable workflow spatially linked the Highway Performance Monitoring System and National Bridge Inventory and applied sequential quality screening to 79,595 open, unrestricted mainline National Highway System bridges in the contiguous United States. The MPI was descriptively characterized using distributional analysis; spatial patterns and specification sensitivity were examined using local Getis–Ord Gi* hotspot analysis and eight alternative formulations. The baseline identified 20,621 bridges (25.9%) as nominally significant exploratory hotspots, concentrated mainly in metropolitan regions and high-demand corridors. Across the alternative specifications, bridge-rank correlations ranged from 0.807 to 0.965, whereas hotspot-set Jaccard similarities ranged from 0.446 to 0.801, indicating greater sensitivity in hotspot membership than in overall rankings. The MPI does not measure realized delay, congestion, reliability, user cost, or investment benefit. Instead, it provides a nationally scalable screening method that identifies bridges and regions warranting further engineering and operational evaluation during preservation planning.