| Summary |
Yuan-Kai Peng, 2006.06
Graduate Institute of Transportation Science, Tamkang University
Due to the rapid development of intelligent transport systems (ITS), there are apparent effects on improving traffic jam issues, saving energy and promoting safety of transportation in recent years. Among them, Advanced Transportation Management Systems (ATMS), has been the core of development in ITS all the time. The main functions include real time traffic flow detection and traffic control related activities. In addition, Advanced Traveler Information Systems (ATIS) also become the key item of development in ITS. If the information of ATMS and ATIS can be integrated in the future, it besides can carry out the traffic control strategies effectively, also can provide correct traffic information to road users at the same time.
A macroscopic traffic flow model is established to estimate travel time in this study. In addition, this study joins the concept of approach delay to discuss suitability of intersection delay models under various traffic situations. With systematic analysis, this study intends to develop a travel time estimation model that is suitable for urban arterials of Taiwan.
An experimental design was conducted for travel time estimation by using the control factors, such as level of flow and the length of link to analyze the criteria for vehicle detectors allocation under various needs of traffic information. For which can verify the travel time estimation models and the location of detectors that is suitable for urban arterials.
The MAPE values were calculated to evaluate the proposed travel time estimation models and the installation criteria for vehicle detectors. In the issues of travel time estimation, the results were promising in view of most travel time estimates are statistically accepted. The best models are Oh model to match up the suitable delay models under various traffic situations. The MAPE values are all around 15%. In addition, the estimate performances are shown to be comparatively steady and consistent while installing single detector. The optimal detector location was identified to be about mid-block position from upstream intersection, and under some specific traffic situations, there were trade-off locations for vehicle detectors installation. In addition, link travel time estimates obtained by using pair-wise detectors is slightly better than that of using single vehicle detector, however, in view of the high cost of vehicle detector, it is suggested to install one vehicle detector at most in a single link on urban arterials.
Finally, the installation criteria for vehicle detectors under various needs of traffic information are proposed, which can provide a guideline for reference to the traffic authorities. |
