Reinforcement learning (RL) has been applied to solve ramp-metering problems and attracted increasing attention in recent studies. However, improving traffic efficiency is the main concern of these applications, and the issue relating to user equity has not been well considered. A new RL-based system is developed in this paper to deal with equity-related problems. With the definition of three RL elements, including reward, action, and state, this system can capture the information of user equity and balance it with traffic efficiency. Simulation experiments using real traffic data collected from a real-world motorway stretch are designed to test the performance of the new system. Compared with a widely used ramp-metering algorithm ALINEA, the new system shows superior performance on improving both traffic efficiency and user equity. Specifically, with suitable parameter settings, the new system can reduce the total time spent (TTS) by motorway users by 18.5% and maintain an equally distributed total waiting time (TWT) with a low standard deviation for TWT across on-ramps close to 0.

This paper studies the multistage pricing and seat allocation problems for multiple train services in a high-speed railway (HSR) with multiple origins and destinations (ODs). Taking the maximum total revenue of all trains as the objective function, a joint optimization model of multistage pricing and seat allocation is established. The actual operation constraints, including train seat capacity constraints, price time constraints in each period, and price space constraints among products, are fully considered. We reformulate the optimization model as a bilevel multifollower programming model in which the upper-level model solves the seat allocation problem for all trains serving multiple ODs in the whole booking horizon and the lower optimizes the pricing decisions for each train serving each OD in different decision periods. The upper and lower are a large-scale static seat allocation programming and many small-scale multistage dynamic pricing programming which can be solved independently, respectively. The solving difficulty can be significantly reduced by decomposing. Then, we design an effective solution method based on divide-and-conquer strategy. A real instance of the China’s Wuhan-Guangzhou high-speed railway is employed to validate the advantages of the proposed model and the solution method.

The energy‐efficient optimization of the train timetable should be carried out on the basis of meeting passenger demand and determining the train operation plan. This paper proposes an integrated energy‐efficient optimization framework for the train timetable. Firstly, two energy‐efficient optimization strategies for this problem are proposed: inter‐station running time allocation and regenerative braking energy utilization. The first strategy aims to reduce the traction energy consumption, realized by selecting the profile based on a given set of speed profiles for each inter‐station sector when ensuring a stable travel time of train routing. The second strategy is intended to fully utilize the regenerative energy feedback from braking trains, realized by setting the departure time of trains based on a small‐range headway adjustment. Then, an integrated energy‐efficient optimization model of the timetable is developed and solved using the genetic algorithm. Finally, a case study of the Guangzhou Metro Line 8 is presented to verify the effectiveness of the method. The results show that the utilization rate of regenerative braking energy in the optimized timetable increases by 8.60%, and the total energy consumption decreases by 9.52%. Regenerative energy utilized roughly doubles during peak hours and increases more than twice as much during off‐peak hours.

This paper is devoted to designing a mixed-integer linear programming approach to solve the simultaneous line planning and timetabling problem on rail networks with a pre-specified set of candidate trains. We first construct a directed graph consisting of two types of nodes and four types of directed arcs to represent the combinational travel network for both candidate trains and passengers. Through this graph, it is easy to simultaneously describe the operation choices of candidate trains, such as whether or not to operate and whether or not to stop at stations, the travel choices of passengers, and the restrictive relations among train operation and passenger travel. Based on the constructed directed graph, a mixed-integer linear programming model with many binary and non-negative integer decision variables is built to simultaneously optimize the line plan, timetable, and passenger travel choices, which can be efficiently solved using the commercial solver CPLEX for small and medium scale network, while a decomposition strategy is required to combine with CPLEX for large-scale network. A set of numerical experiments are carried out to analyse the impacts of the passenger flow sub-unit division, number of candidate trains, and weight factors of two objectives on the solutions. Finally, we conduct two case studies for testing the practicability of our proposed method.

The contradiction between transport capacity and passenger demand in urban rail transit is usually prominent during peak hours in some megacities of China, and some passenger flow control measures have been adopted to alleviate passenger congestion. To better save passengers' travel time when taking passenger flow control measures, this paper proposes an integrated optimization method of bus route adjustment with network-level passenger flow control for urban rail transit, in which the controlled passengers can freely choose to shift to bus or to retain in urban rail transit for pursuing a lower travel cost. With the objectives of minimizing average additional travel time for all affected passengers and maximizing the operating revenue of urban rail transit, an integer non-linear programming model is formulated to determine the inbound passenger volumes and bus adjustment schemes. To solve this proposed model effectively, a multi-objective particle swarm optimization based on dual-population co-evolution is designed. Finally, three sets of numerical experiments, including an integrated optimization experiment and two independent optimization experiments of passenger flow control, are implemented to demonstrate the feasibility and benefits of the proposed method.