Estimation of a Fundamental Diagram with Heterogeneous Data Sources: Experimentation in the City of Santander

The reduction of urban congestion represents one of the main challenges for increasingsustainability. This implies the necessity to increase our knowledge of urban mobility and traffic.The fundamental diagram (FD) is a possible tool for analyzing the traffic conditions on an urbanroad link. FD is commonly associated with the links of a transport network, but it has recently beenextended to the whole transport network and named the network macroscopic fundamental diagram(NMFD). When used at the link or network level, the FD is important for supporting the simulation,design, planning, and control of the transport system. Recently, floating car data (FCD), which arebased on vehicles’ trajectories using GPS, are able to provide the trajectories of a number of vehiclescirculating on the network. The objective of this paper is to integrate FCD with traffic data obtainedfrom traditional loop-detector technology for building FDs. Its research contribution concerns theproposal of a methodology for the extraction of speed data from taxi FCD, corresponding to a specificlink section, and the calibration of FDs from FCD and loop detector data. The methodology has beenapplied to a real case in the city of Santander. The first results presented are encouraging, supportingthe paper’s thesis that FCD can be integrated with data obtained from loop detectors to build FD.