Macroscopic fundamental diagrams for Stockholm using FCD data

Abstract: Macroscopic fundamental diagrams (MFD) reveal the relations among flow, speed and density in a large geographic region. After literature review on macroscopic analysis, the similar methodology is applied in this thesis. The purpose of the thesis is to find the evidence that is able to prove MFD existing in Stockholm urban region. Both floating car data (FCD) based on global positioning system (GPS) data from taxis travelling in Stockholm region and traffic data from fixed detectors data source are used to construct the fundamental diagrams. Geographically, the usage of data is extended from single link to multiple links, then to the entire study region. The temporal phase is restricted in one weekday and weekend. The diagram of flow vs. speed based on single detector is found disordered, by contrast, the diagrams of cumulative flow, speed and density for all detectors represent orderly. MFD diagrams proposed in Yokohama case study by Geroliminis and Daganzo are reproduced with cumulative data in this thesis.  Therefore, it can be proved that MFD exists when using data from multiple links. However, the cumulative data from fixed detectors only represents the traffic on links where they locate, not the entire region. To overcome it, GPS data from taxis, which covers the whole region, is analyzed with same method. Because full taxis travel in the same manner as normal vehicles, they are selected to approximate traffic in whole region. A neat curve of flow vs. speed is produced and it coincides with corresponding diagram in the reference paper. It enhances the conclusion that MFD exists in the entire study region. Moreover, based on the constant ratio between average link flow and region exit flow, a controlling density policy is discussed in aiming for maximizing trip completion.