Road Connectivity and Relative Market Accessibility in Chinese Cities: Spatial Inequality and Long-Run Decomposition

Improved road connectivity need not produce equivalent gains in access to economic opportunities. Using modeled intercity travel times and city GDP for 278 Chinese cities during 2000–2023, we compare physical network reach with relative external market accessibility (EMA), which weights inverse road times by each origin’s external destination GDP shares. Analysis combines trends, relative and absolute inequality, spatial clustering, rank mobility, regional comparisons, and two-factor Shapley accounting. Mean intercity travel time fell by 28.7%, while relative EMA rose by 39.6%. Although relative inequality declined after 2010, absolute city-level gaps widened, spatial concentration persisted, and 202 cities occupied the same quartile at both endpoints. Nationally, the road-time component represented 97.0% of observed relative EMA growth. Northeast China reveals a sharper regional contrast: shifts in destination GDP shares offset 65.8% of favorable road-time contributions under the baseline measure, primarily through declining relative weight on other Northeast destinations. This component persists across alternative distance-decay parameters, origin weights, denominator definitions, and a targeted administrative-boundary exclusion. An exploratory comparison using city-reported growth rates to construct a comparable-price opportunity proxy also retains the negative component, although the offset magnitude and net EMA movement are sensitive to the GDP treatment and decay specification. These findings establish a transferable diagnostic sequence for regional planning: monitor connectivity and opportunities separately, assess persistent territorial disparities, and investigate destination composition alongside observed freight and economic interactions before setting intervention priorities.