Optimal public transport timetabling with autonomous-vehicle units using coupling and decoupling tactics

Fluctuating demand for public transport (PT) is one of the main reasons for unreliable PT service, and subsequent passenger frustration at being left behind at PT stops. A novel way to solve this situation is to optimally use autonomous PT vehicles with coupling and decoupling (C&D) of vehicle units to accommodate the fluctuating PT demand and reliability issues. In this way, vehicle size is added as a variable of the problem. This work proposes a new class of C&D tactics in the process of solving the problems of PT route timetabling subject to passenger demand. Resolving the optimisation problem involves determining the C&D arrangement at stops/stations to accommodate the C&D options and departure times. The validation of the model is performed by a small example and a real case study with a bilevel heuristic algorithm that manages to completely (100%) eliminate left-behind passengers using practical, even-headway, and even-load timetables.