The Amsterdam Practical Trial (APT) is a multi-year programme that has been initiated by the Dutch Ministry of Transport and the Environment and which is carried out in close cooperation by Rijkswaterstaat, the city of Amsterdam, the province North Holland, the Amsterdam Metropolitan Region, and the Delft University of Technology. The APT has been aiming at the integration of innovative road-side and in-car developments at a network-wide level. After the proof of concept was finished in 2009, two parallel tracks started in the Amsterdam region: the road-side track (aiming at an innovative, automated working system with ramp-metering and traffic lights for a better use of the network), and the in-car track (aiming at individualized travel and traffic information in the car both for commuter traffic and for large event traffic).
In this talk, we will focus on the innovative road-side system of the APT. In the first, we will focus on the system architecture and the overall controller design. We will explain which principles are applied in order to use the urban arterials as storage locations for freeway metered traffic, as well as to solve problems occurring on the urban arterials themselves, e.g. in case of spill-back or gridlock issues. We explain the key monitoring and control principles, and analyze the resulting feedback controller showing how to choose its parameters to ensure stability and minimize the time needed to achieve the target value. To this end, a new methodology is proposed to analyze the dynamics of the controller in relation to the control parameters for different controller designs.
While the development of this system started in 2012, the system became operational in April 2014. After all technical and functional tests were completed, the system parameters were tuned, finalizing the implementation phase. Starting April 14, a period of eleven weeks was taken to collect the data for the ex-post assessment. This was done by switching the system on and off every week, so that a fair comparison could be made. From the collected data, it could be concluded that while the system caused additional delays on the urban network and ramps, the throughput on the freeway arterial was improved. Even more important, detailed analysis of the data shows were the system performed as expected, but also which improvements can be made to further increase its effectiveness. These so-called ‘optimizations’ are discussed in this talks, as are the expected impacts of implementing these in the system. We will also discuss how these are operationalized in the next phase of this innovative project.