Antecedents of Spot and Contract Freight Mix in the Truckload Sector

Truckload carriers face tradeoffs in their effort to build their freight networks from combinations of spot market and contract shipments. These tradeoffs exist because contract freight provides loose volume guarantees but lower linehaul rates, whereas spot freight commands higher linehaul rates while being more stochastic in nature. The issue of carriers’ mix of spot market and contract freight, while of utmost importance in practice, has received limited theoretical and empirical attention. Drawing on dynamic transaction cost theory, we develop middle‐range theory that explains why carrier traits such as size and use of team drivers as well as characteristics of the freight markets in which they are embedded impact carriers’ reliance on spot market instead of contract freight. To test our theory, we rely on archival survey data collected by CarrierLists, a firm that specializes in compiling and disseminating motor‐carrier information. Our econometric estimates corroborate our theory and remain after robustness testing. Apart from extending theory regarding dynamic transaction costs, our findings have important implications for carriers, brokers, and shippers.