Resource access roads present the extremes of problems associated with soft subgrades, extremely heavy axle loads, and very low traffic volumes. The very low cost tolerance associated with these roads has led designers to adopt access road structure designs using geosynthetics. Design methods which talce rut depth as the key criterion exist. However, road stiffness has a large impact on vehicle operating costs and after all, the roads are built for the vehicles. Therefore, against the background of the significance of overall truck transportation system design and costs, considering the relationships between the roads and the vehicles using them, a long term project to examine geosynthetic-built access road stiffness was embarked upon. The results to date are presented.