Pessimistic Equilibrium Flow and Its Network Design Implications
Quality of service in urban transportation network is very important to the users of this network. Travel time in street networks is one, very important, aspect of this service, particularly for trips with purposes such as work or school. A conservative route choice concept based on a pessimistic view of travel time has been proposed to render a pessimistic equilibrium flow (PEF). This flow is different from a user equilibrium flow (UEF), particularly in congested networks, and has sometimes a lower total travel time than UEF. A street network design problem has been proposed to take into account the travel time fluctuations (or service quality) in the network. This design model is based on PEF and is called pessimistic network design (PND) model. It is shown by an example network that an implication of PEF consideration in a PND model is that projects with lower potential in getting congested are chosen as compared with the conventional network design problem.