Vehicles have an impact on environmental pollution through emissions. Thus, they generate different carbon footprints, or emit different amounts of carbon dioxide into the atmosphere. This article attempts to determine the effects of carbon dioxide on the distribution of the traffic stream in the selected part of the transport network. For the analysis the Warsaw-Krakow route was chosen. The movement between these two cities can be performed with different modes of transport. The distribution of the passenger streams was conducted for three variants of the three sub-criteria: minimum average costs, minimum marginal costs and the costs of environmental pollution. The unitary cost of carbon dioxide emission was determined using a CO2 Calculator. The selection of the variant of the passenger stream distribution was carried out using a multi-criteria evaluation method called MAJA.