The purpose of this thesis is to find out if it is possible to introduce a higher gross weight of trucks, from the current 64 tonnes to 74 tonnes. It would mean that the Swedish transportation would be more efficient and it would strengthen the Swedish business sector 's international competitiveness and also support the continued productivity, thus an efficient forest infrastructure is the key to obtain this. The report's input are from literatures, the Swedish Forest Agency’s recommended width increases of the road and simulations based on radius and angle of the curves. The results are based on calculations made ​​from the input data. The results of the report shows that the Forest Agency’s recommended width increases are enough to drive a 74 tonnes truck, which means that the 74 tonnes trucks are useable in the forestry after adjustments of the road. An increase from 64 tonnes to 74 tonnes would from an environmental point of view reduce carbon dioxide emissions by up to 11% and also the road would be better preserved when the axle load is distributed in a more efficient way.