The Long-Run Dynamic Impact of Light Rail Construction on Regional On-Road CO2 Emissions Per Capita

Employing a cutting-edge quasi-experimental event study estimator from de Chaisemartin and D’Haultfœuille (2024), the results of this paper indicate that light rail construction has a significant impact on reducing regional CO2 emissions per capita, and that these effects change dynamically for at least 20 years after construction. The paper categorizes these long-run effects into four phases of light rail operational effectiveness: an early “establishment” phase where observed effects on per capita emissions are relatively small, an “early growth” phase of increasing effectiveness, a “stagnation” phase where the benefits plateau, and a “maturity” phase of renewed effectiveness.