Previous studies have suggested that the use of high-capacity transportation (HCT) can lead to low-carbon road-transportation in the forest industry. This study shows the impacts (in terms of energy efficiency) of a three-year adaptation process of transportation (2014–2016) towards HCT that took place in a synchronized transportation system (STS). The use of three transportation fleet-management control (TFMC) methods was analyzed in various road infrastructures. Energy-efficiency calculations were undertaken based on the HCT vehicles’ mass limits (64, 68 and 76 t). The use of 76 t vehicles increased energy efficiency by 13.4% and reduced CO2 emissions by 3.5% (to 49.6 g/tkm). In addition, the results show that the energy efficiency of the STS could be improved by a further 3.1%. In this respect, the proposed TFMC was used to adjust the STS towards vehicle-group transportation while meeting the road-class constraints of local wood supply chains. Forest-industry companies in Finland and abroad can use the tailored TFMC to optimize the STS in the near future and to achieve the energy-efficient STS and the regulations of the European Commission in wood-procurement logistics.