Designing the Westerscheldetunnel Toll Plaza Using a Combination of Queueing and Simulation

This paper describes how a combined queueing and simulation study was successfully executed for the design of a toll plaza. The objectives of the study were twofold: • to configure the types of toll booths with multiple payment functionalities (cash, credit cards, and electronic payment). • to determine the number of toll booths for each type. The model was also used to validate the spacing, safety, and accessibility of the toll plaza. A hybrid approach of simulation and queueing theory proved to be a powerful method in analyzing the queueing processes of the toll plaza. This approach combined the insights from queueing theory with the practical applicability of simulation. Queueing theory provided the conceptual framework and limited the number of variants to be examined, while simulation was used to compare and evaluate the variants. The study showed that fewer toll booths were needed when different payment systems were separated, as a combination of different payment systems at one toll booth would substantially enlarge the variability of service times. This variability appeared to dominate the 'inefficiency' of separate toll booths which may seem counterintuitive. Consequently, the initial design had to be completely redesigned.