A New Perspective On Returns To Scale For Truckload Motor Carriers

Understanding how motor carriers' size affects their productivity (e.g., miles per power unit) is of fundamental importance to carrier managers, shippers, and investors, because the nature of this relationship should influence carriers' strategies with regard to growth. In the truckload (TL) sector, the prevailing assumption is that TL carriers face constant returns to scale such that productivity differs little between large and small carriers. While empirical findings from several studies conducted since deregulation are consistent with this assumption, we contend that the true relationship between carrier size and productivity is more nuanced and is contingent on carriers' level of technical efficiency. Specifically, we develop and test middle range theory that predicts increasing returns to scale for carriers with low technical efficiency, constant returns to scale for carriers with average technical efficiency, and decreasing returns to scale for carriers with high technical efficiency. We test our theory by estimating production functions using quantile regression for data collected from the U.S. Department of Transportation for 1,068 TL carriers. Results from our analyses corroborate our predictions. Our findings hold valuable implications for the logistics literature as well as TL carrier management, shippers, and other industry stakeholders.