Port Capacity Expansion Under Hinterland Constraints In Turkish Seaports

This paper investigates the Hinterland Bottleneck Effect (HBE) in Turkish seaports using a revisedidentification strategy that avoids mechanical endogeneity inherent in ratio-based dwell timemeasures. Instead of relying on imputed dwell time, we employ directly observable system-levelperformance indicators—container throughput growth, throughput volatility, and deviations fromtheoretical steady-state conditions—as dependent variables. Using panel data from twelve majorTurkish container ports over the period 2010–2023, we examine whether hinterland capacityconstraints are associated with throughput saturation, heightened operational volatility, andsystematic departures from Little’s Law equilibrium predictions (Little, 1961). Causal identificationof the HBE is anchored in rail connectivity activation, interpreted as a quasi-experimental shockdriven by long-term infrastructure planning rather than short-run port conditions. Fixed-effectsestimates indicate that hinterland constraints are significantly associated with higher throughputvolatility, while port-side capacity expansion shows no significant relationship with throughputgrowth when hinterland capacity is binding. Rail activation generates statistically significantstructural breaks, reducing volatility by approximately 18 percent and shifting system behaviorcloser to steady-state benchmarks. Quantile regression results further reveal that these effects areconcentrated in the upper tail of the volatility distribution. Overall, the findings confirm that theHBE reflects a genuine system-level phenomenon with important implications for infrastructuresequencing in emerging market port systems.