This paper explores using a decision support tool, an already developed and preliminary tested system with highly parameterised Simulation and Optimisation engines. This tool manages the assignment of user requests to an intermodal transport system in which conventional transit transportation modes, buses, subways, railways, and trams, are complemented and coordinated with a ride-pooling service. The main objective of this paper is to evaluate the suitability and sustainability of the intermodal transport system in terms of the reduction of emissions, number of conventional trips, and the policies efficiency depending on variable fleet sizes, detour penalties sensibility and fares. The computational tests have been conducted with a realistic Barcelona Metropolitan Area model. The results indicate a significant reduction in emissions with the implementation of ride-pooling services, both in multimodal and intermodal approaches, contributing to alleviating urban traffic congestion caused by private vehicles. The findings also demonstrate the efficacy of integrating an adaptation of the detour factor, minimising the fare increment for already en-route passengers, and ensuring the assignment of more suitable detours that redure additional costs for passengers already in transit. The effects on fare and travel time are analysed. Furthermore, the implementation of a variable active fleet policy involving a gradual adjustment of the operating number of vehicles during the start-up and shutdown of the system proves to be beneficial for the company in mitigating the system’s operational costs, especially in periods of lower demand, where maintaining a full-time fleet would incur in unnecessary expenses given the limited number of requests