Vehicle manufacturers are developing new technologies for self-driving vehicles presumably replacing today’s manually driven vehicles. The purpose of this study is to apply cost-benefit analysis of expected benefits and costs with an increasing share of self-driving vehicles on the Swedish roads, and to find out which effects are most important for socio-economic profitability. Self-driving vehicles lead to reduced generalized costs for transportation. The most important benefits in the example calculations are the reduced need for drivers of lorries and decreased time cost for drivers of cars. Passenger traffic contributes with the largest part of both benefits and costs, because it represents the major part of the traffic on the roads. The net benefits are however larger for freight, because the entire cost for the driver disappears. Capital costs for the new vehicles are an important factor, but the effects on safety, saved fuel and emissions due to platooning and smoother driving are relatively small.