Research on the coupling coordination between transport accessibility and socio-economic development in plateau mountainous cities: a case study of Qujing City

Introduction Exploring the coupling coordination between transport accessibility and regional socio-economic development is crucial for the sustainable development of plateau mountainous cities. Methods Taking Qujing City on the Yunnan-Guizhou Plateau as the study area, this study constructed a geographic element dataset and utilized the raster cost distance method, multi-indicator comprehensive evaluation, and coupling coordination degree model to analyze the evolution of transport accessibility and its relationship with socio-economic development from 2014 to 2024. Results While transport accessibility improved significantly— with the average travel time reducing from 3.32 to 1.06 h—it exhibited distinct “mountain-flatland” differentiation, where the 1.5-h isochrone expanded from the central flatland to peripheral mountains. Furthermore, although improved accessibility helped narrow the socio-economic gap between flatland and mountainous areas, the “center-periphery” development structure remained largely unchanged. Consequently, the coupling coordination degree showed a positive trajectory but maintained this spatial disparity; flatland counties in the central area achieved primary coordination, whereas other regions remained near discoordination and marginally coordinated. Discussion and conclusion As regional integration and the construction of peripheral infrastructure accelerate, the developmental divide in these plateau regions is gradually closing. Future policy should leverage improved accessibility to catalyze industrial transformation and the development of specialized mountain economies, ultimately bridging the socio-economic divide between mountain and flatland areas.