Road freight accounts for 89% of the inland freight transportation in Turkey. This study examined the factors affecting capacity utilization in Turkey with a specific focus on load factors and empty running. These two decisions, the load factor and the choice of running empty, are modeled jointly in a Heckman model. The model results showed that rigid and articulated trucks represent relatively different transport markets. Their age and the distance profile of the shipments affect the load factor and the probability of running empty. These effects are further examined for different commodity types and by testing different econometric specifications.