The spatial impact of high bridges on travel accessibility and economic integration in Guizhou, China: a scenario-based analysis

As crucial fixed links of the transportation systems, high bridges play an essential role in overcoming geographical barriers in mountainous areas. Despite their importance, comprehensive evaluations of the collective spatial-temporal effects of multiple high bridges across broad regions are lacking. This study addresses this gap by analyzing the impact of 295 high bridges in Guizhou, China, on travel accessibility and economic potential through spatial analysis under scenarios with and without these bridges. The aim is to quantify their contributions to accessibility and assess their impacts on regional economic integration from 2000 to 2020. The findings reveal that high bridges significantly improved travel accessibility and economic potential within counties, with the average contributions being the greatest for the period 2010–2015 within the whole study period. High bridge construction promoted accessibility convergence and economic integration, reducing regional disparities. The decline in the coefficient of variation (CV) of accessibility demonstrated a converging effect; while the CV of economic potential showed an initial growth followed by a decline. Economically disadvantaged counties gained the most in accessibility and economic potential, highlighting the role of high bridges in regional integration. This study proposes a framework for accurately measuring the economic benefits of high bridges, providing insights for future transport planning in isolated mountainous counties and supporting economic development in regions with underdeveloped transportation infrastructure.