Within this project, the mean travel speeds and further traffic charecteristics of freeway facilities are investigated while taking into account the interactions between the successive components of the facility. Based on the outcomes of the research, a novel methodology implemented in a computer program was developed in Microsoft Excel that facilitates the assessment of oversaturated freeway facilities. The methodology of german HBS 2015 may only be applied if none of the segments and junctions shows level of service F. The new approach overcomes this limitation by enhanced models that also apply to oversaturated states. Emprical analyses for two test routes (Munich and Karlsruhe) with additional microscopic simulation models provided the data basis. First, an application of the U.S. HCM-based program FREEVAL was tested for the evaluation of german freeways. The simulation with FREEVAL showed plausible results for the test route in Karlsruhe. Because of basic discrepancies between the methodologies of HCM and HBS, mainly in the definitions of capacity, time intervals, q-V-relations and the key quality criteria, the application of the U.S. FREEVAL for german freeways is not recommended. This lead to the decision to develop a model which is closely connected to the HBS-methodology. Therefore, macroscopic traffic flow models were compared towards german standards. The Cell Transmission Modell (CTM) from DAGANZO was chosen as a candidate for the model implementation. In comparison to the U.S. FREEVAL, the discretization in the german model was refined. The finer structure leads to a more explicit modeling of the congestion propagation without additional model extensions. The data model of CTM is generally very suitable for modeling road sections such as stretches of freeway facilities. Federal freeway BAB A 99 near Munich was modelled with data sets of four days with different congestion patterns. The results show that the german version of FREEVAL allows for a realistic reproduction of the traffic situation. In case of severe overloads, discrepancies in congestion speeds occur, which originate in the type of traffic flow model used. The new tool can be recommended as an alternative to microscopic simulation for design tasks and for comparing different scenarios in addition to using HBS. It is not suitable for reproducing congestion events with exact spatio-temporal specifications. (Author/publisher)
Samenvatting