Subway opening enables urban green development: Evidence from difference-in-differences and double dual machine...

Area of Science:

• Urban planning and development
• Environmental economics
• Transportation infrastructure

Background:

• Urban rail transport is crucial for sustainable urban development.
• Limited research exists on the impact of subway systems on urban green development.
• This study addresses the gap by examining subway opening's effect on urban green total factor productivity (GTFP).

Purpose of the Study:

• To investigate the influence of subway opening on urban green total factor productivity (GTFP).
• To explore the mechanisms through which subway systems impact urban green development.
• To analyze the heterogeneity of this impact across different urban characteristics.

Main Methods:

• Utilizes Chinese data from 281 prefecture-level cities spanning 2008-2021.
• Employs difference-in-differences (DID) and double dual machine learning (DDML) methodologies.
• Conducts robustness tests to validate findings.

Main Results:

• Subway opening significantly improves urban GTFP, promoting green and innovative development.
• Mechanisms include broadening production frontiers, advancing technological progress, upgrading industrial structure, and enhancing innovation capacity.
• The impact is heterogeneous, being stronger in larger cities, those with high green development levels, and influenced by digital infrastructure and regional competition.

Conclusions:

• Subway infrastructure is a key driver for enhancing urban GTFP and achieving sustainable urban growth.
• Policy implications suggest leveraging transport infrastructure for targeted green development strategies.
• Economic growth targets significantly moderate the positive impact, unlike environmental targets.