In order to achieve the main objective of the project, the following sub-objectives/steps are considered:
- The design or selection of a triggering rule that estimates what kind of congestion the system is showing (if any): “recurrent congestion”, “shock waves” or “unexpected capacity reduction”.
- The design or selection of a controller that works for each kind of congestion. During the design process, the proposed algorithms will be simulated and tested using real-life or synthetic data that was previously used in other papers and that can be useful for each kind of congestion. For shock waves, the SPECIALIST algorithm will be used. This algorithm has been already successfully designed, simulated and tested by TU Delft researchers. For recurrent congestion, a control algorithm will be designed that combines an off-line computed solution (using MPC) with a linear feedback controller that takes into account the difference between the off-line computed traffic states for the typical recurrent congestion and the actual traffic states measured on-line. For unexpected capacity reductions, an easy-to-implement controller (e.g. a logic-based controller) will be designed that is able to properly reduce the congestion (minimizing the TTS or maximizing the output flow) when a capacity reduction appears and that can be easily implemented in real time.
- The collection of a loop detector data set from the SE-30 ring-road in Seville. The freeway includes the Centenario Bridge, which is a bottleneck that creates, during the peak hours, the biggest recurrent congestion in the region. This benchmark has been previously used by the Experienced Researcher (ER) for the evaluation of algorithms for the dynamic operation of reversible lanes.
- The testing and evaluation of the proposed controller in two real freeways that show the three main kinds of congestion allowing an objective evaluation of VSL control and a comparison with previously proposed techniques. In addition to the freeway in Seville for which data will be collected, the controller will be also simulated using the A12 freeway in The Netherlands. Traffic data from A12 is already available from Regiolab-Delft (http://regiolab-delft.nl/) that has a huge database containing data from the inductive loop detectors and variable message signs on the national highways in the province of South Holland. Moreover, A12 have been used for the field test of the SPECIALIST algorithm6 allowing a suitable estimation of the speed dynamics.
- The analysis of the economic and social improvements that can be obtained by the implementation of VSL in congested freeways around European large and medium-sized cities applying a Benefit-Cost Analysis. This sub-objective includes the analysis and comparison of the different performance criteria that may be considered. This analysis will be based on the two benchmarks: SE-30 and A12.
- Dissemination of results and communication towards the technical (at international level) and non-technical (at local level) community in order to show the potential performance that can be achieved using the newly developed VSL control strategy.