Robust Optimization of Dynamic Motorway Traffic via Ramp Metering

This paper presents a robust optimization model for motorway management. The optimization aims to minimize motorway delay via ramp metering with consideration of uncertainties in traffic demand and its characteristics. The robust optimization is formulated as a minimax problem and solved by a two-stage solution procedure. The performances of different control policies are illustrated through working examples with traffic data collected from the M25 motorway in the United Kingdom. Experiments reveal that the robust control provides reliable performance over a range of uncertain scenarios. Results also show that the proposed robust controller is particularly effective during transition periods when congestion has not yet fully developed.