Longer and heavier vehicles (LHVs) have been permitted to operate in Sweden. Since 1996 and as of the beginning of 2015, the maximum gross vehicle weight of 60 tonnes and a length of up to 25.25 m have been permitted. The Swedish Transport Administration has decided to further increase the maximum gross vehicle weight to 74 tonnes. The axle load limits are on the other hand not increased. This will therefore increase the number of multiple axle groups (i.e. tandem and tridem axle groups) per heavy vehicle. Studies are under way to evaluate the impact of the proposed LHVs on the existing transport infrastructure. Repeated load triaxial tests and indirect tensile fatigue tests have been conducted on selected conventional asphalt mixtures to investigate and quantify the impact of single, tandem and tridem axle configurations on permanent deformation and fatigue performances of conventional asphalt pavements. In addition, fatigue tests for selected LHV scenarios were conducted. This paper presents the results of the laboratory tests and simulations conducted. The test results have clearly demonstrated the impact of the different axle configurations on the rutting and fatigue performances of the mixture. Furthermore, such results can explain the significance of axle configuration on the rutting and fatigue performances of asphalt pavements.