The objectives of the Harbour Tunnel in Copenhagen were to bring about changes in the traffic flows and to yield revenue. The evaluation of these changes, that is whether they bring about overall benefits, required an accurate forecast of traffic flows on all affected roads and public transport systems but in particular in the tunnel itself. Forecasts of traffic flows were therefore required, under future circumstances with and without the tunnel. Both freight vehicle and passenger car forecasts were required; consideration was given early in the project to a special study to predict cycle flows through the tunnel but this idea was not pursued. Cycle flows, however, are predicted and assigned in the main model system. The general proposal for the construction of a Harbour Tunnel incorporates a number of alternative alignments of the tunnel and more particularly of its approach roads. a) For the covering entry of this conference, please see ITRD abstract no. E213537.