Competitive transit network design in cities with radial street patterns

• An analytical transit design model is developed for the case of radiocentric cities.
• The model is defined by a simple network structure in the central city area.
• This model responds well to the network design with only a limited volume of data.
• A high performance bus (HPB) is the best option to promote urban transit mobility.
• The defined network is characterized by a certain central area size and low headways.

This paper presents a reformulation of the hybrid model developed by Daganzo (2010) to extend its applicability to a greater number of cities, especially those characterized by a radial street pattern. The new transit network structure is also composed of two types of schemes: radial/circular in the central area and hub and spoke in the periphery. This analytical model defines the optimal network layout through minimizing its objective function, which is composed of agency and user costs. Its decision variables are central area size, headway, line spacing, and stop spacing. In this reformulation, stops with single coverage, those only served by one line, are introduced in the hybrid model to improve spatial accessibility to avoid an increase in agency investment. This model is a tool to design competitive transit systems topologically characterized by simple schemes adapted to the urban structure and concentrated transit flows, and also operatively by high frequencies and speeds. Ultimately, all this allows for easy use and management of transit networks.The model’s robustness with regard to input parameters and decision variables reinforces its results and estimates what implementations on real road networks would be like. It presents coherent behavior regarding real-world standards, where high, concentrated and temporally well distributed demands lead to more efficient and effective transit systems. High performance bus (HPB) is the transport technology used throughout this paper because, as has been proved in this paper, it is the best transit mode in urban areas for a wide range of demand values. Main system characteristics have been obtained such as central areas greater than a 25% of the city, low headways of around 2 min, high commercial speeds ranges between 14 and 17 km/h, and suitable spatial accessibility, where stop spacing moves between 350 and 550 m.