The viability of implementing a new alternative intermediate transport mode in the Lisbon, Portugal, metropolitan area was examined. The intention of this new system was to combine the major strengths of both public transport and private vehicles to provide a competitive transport alternative for commuters from low and intermediate density areas, who do not create enough demand to sustain a high-quality public transport service. Conventional public transport systems can provide efficient space and energy consumption, whereas private vehicles have high levels of flexibility and are fast and always available. A comprehensive methodology is presented to encompass the generation of input data of the model on the basis of transport demand data involving spatial-temporal constraints, the possible location of the service stops, and the detailed characterization of the service operation. The global objective of the model is to design a self-sustainable system that would maximize the operator's profit, not one that would satisfy all potential demand. The developed model uses supply parameters obtained through current bus operators in the region. However, the estimated values should be refined before service deployment. This assessment was performed, as an initial test bed for Lisbon and will be expanded to the whole metropolitan area. Results suggest that this service might be significantly profitable to the operator and a good alternative for single private car drivers. Implementation of this system may relieve some congestion during peak periods.