The knowledge of the effects which the vertical alignment of a road produces on traffic is necessary for preparation of appropriate standards and recommendations relating to gradients and to vehicle-climbing lanes. Furthermore this knowledge constitutes an indispensable element of the information which is required for economic calculations in traffic engineering. In fact, very extensive information is needed in order that the abovementioned effects may be determined in a satisfactory manner. Among other things, it is necessary to know the geometric road design features, the traffic volume, and the classification of traffic according to type of vehicle. Moreover, it is required to know the effects of the vertical alignment on free-moving vehicles of various types, and the influence of sight conditions and opposite-direction traffic on the frequency of overtaking and passing. A complete treatment of this problem will be carried out with the help of simulation by means of automatic data processing equipment. A model for simulation of traffic on two-lane roads is at present in preparation at the National Swedish Road Research Institute. As has been pointed out in the above, the necessary basis for the simulation comprises, among other things, the knowledge of the effects produced on free-moving vehicles by the vertical alignment of the road. Studies of the variations in the speeds of free-moving vehicles with the distance on upgrades have therefore been made for this purpose and the results are presented in this report.