Maximal demand coverage transit network redesign with resource reutilization

Source abstract

With the progressive development of Metro systems, transportation authorities face the problem of adjusting and optimizing existing bus transit lines, considering the new mobility patterns of cities. This paper focuses on a transit network redesign problem seeking to improve the accessibility of citizens to the entire transportation system, which is assumed to comprise metro and bus lines. To this end, it is assumed that resources such as stops marquees and vehicles operating the old transit network can be reused if needed, contributing to reducing the investment required for the network redesign. An optimization model is introduced for the base problem that seeks to support a purely strategic decision making process. In that case, it is imposed that the number of new bus lines is equal to those running in the original network. The problem is then extended by relaxing that constraint and also by embedding several tactical decisions. The latter include the frequency of the buses in each line and the fleet size. The purely strategic problem can be tackled by a general purpose solver for small — to medium-sized instances. Nevertheless, the problem is NP-Hard. Hence, thinking ahead to larger instances, and also considering the above-mentioned extensions a genetic algorithm is also developed. The results of a series of computational tests conducted to assess the relevance of the contributions provided is reported on.