Public transport networks in most major European cities contain both schedule-based and frequency-based services. However, existing methodologies typically optimize these services separately, leading to suboptimal results. To address this, an integrated optimization framework has been established recently, where the frequencies and timetables for the schedule-based and frequency-based services are determined simultaneously. This study is motivated by the need to incorporate the two following critical aspects that have been simplified or overlooked in that framework: (i) additional capacity constraints to mitigate overcrowding, and (ii) transport equity among heterogeneous passengers, especially accessibility for elderly individuals and people with disabilities. The new capacity constraint introduces a hard capacity limit for vehicles, ensuring that passenger loading does not exceed the vehicle’s maximum capacity. It allows for standing passengers once the seating capacity is reached, as long as the total number of passengers remains below the full vehicles´s capacity. In terms of transport equity, we differentiate between two classes of users, namely a large demand segment of regular passengers and a small share of travellers with physical disabilities (PWMD users). Our results show that optimizing for both classes of users can find solutions that significantly improve the travel experience for the minority demand segment, without a significant increase in the travel cost for regular passengers. These enhancements contribute to advancing research in equitable public transport network optimization.
Hoz et al. (Thu,) studied this question.