Today maintenance of existing infrastructure already has gained priority over the construction of new traffic facilities. Thus the efficient utilization of existing facilities and the cooperation of different modes become more and more important. As a result, multimodal considerations and corridor analyses are demanded more frequently. Accordingly, the existing concepts and guidelines for the assessment of traffic facilities have to be revised and extended. The introduction of multimodal concepts requires to analyze those unimodal concepts, which have been updated for decades and to check their general applicability. Multimodal concepts also have to include the findings of mobility research giving evidence for constant travel budgets and for the long-term effects of traffic facilities on land use. Based on these fundamentals, a multimodal concept for the assessment of traffic facilities is developed step by step. Therefore the thesis is divided in three stages. In Part A, at first, performance measures, which are not related to a specific transport mode, are derived. Since traffic is not a goal in itself but a means to realize human activities, an approach is taken which focuses on the transport demand of the user. The results are transferred to private and public transport systems considering their specific characteristics. Based on Part A, Part B presents the revision of existing concepts for the assessment of unimodal facilities. The relevant design parameters and operational factors influencing the facility performance are analyzed. In Part C the results of the preceding parts are incorporated in an extended multimodal concept, which no longer concentrates on vehicles but on the real measure of transport demand, i.e. passengers and goods. Only these units are suitable to take into account the potentials of improved facility and vehicle utilization in order to identify different scenarios how private and public transport on the road and alternative means of transport in the corridor jointly can accommodate a given transport demand under prevailing traffic conditions. Showing different ways of meeting the transport quality target the multimodal concept supports decision-making and the efficient allocation of limited funds.