Analysis of the Effectiveness of the Medan Station Road Overpass in Reducing Traffic Congestion in the Urban Core

Abstract

This study evaluates the effectiveness of the Medan Station Road Overpass in reducing traffic congestion in the urban core of Medan City (North Sumatra, Indonesia). Using a quasi-experimental Before–After design and mixed methods, we compared traffic performance before and after the overpass began operation using peak-hour surveys (morning, midday, and afternoon) and road-user perception data (n = 120) supported by stakeholder interviews. Average vehicle speed increased by 41% across vehicle classes, while traffic volume increased by 11.8%, indicating improved traffic throughput and smoother flow on the corridor. Paired t-tests on aggregated peak-period indicators suggest statistically significant improvements in speed (p < 0.001) and an increase in volume (p = 0.049). User perceptions were positive: 85% of respondents reported improved traffic flow, 82% reported improved comfort, and 79% reported improved safety. However, capacity improvements may attract additional traffic over time (induced demand); therefore, complementary traffic management measures (curbside pick-up/drop-off control, parking regulation, and signal coordination) are recommended to preserve long-term benefits. A key limitation is the absence of a control corridor, which restricts causal attribution.