Urban transit system is an important part of city transportation, which is an interdisciplinary industry, including traffic engineering, operation research, and computer science. To provide smart services for passengers while applying the new technologies, it is necessary to build an optimal transit network and transit service. A smart transit system is processed from strategic planning, tactical planning, operational planning, transit evaluation to marketing and policy. For each stage, large quantities of related literature have been introduced from different perspectives. The aim of this research is to document the main smart urban transit models, topics and implementations for future references and research in each stage. For the planning part, this paper first summarized the objectives, constraints, algorithms, and implications of the models currently in use and classified the objectives and constraints with classic category and new category. The prominent topics and potential research were captured clearly when comparing the two categories. The methodologies for solving those models were proposed and the genetic algorithm and simulated annealing have been mostly used, which will be helpful for filling the gaps for further research. Despite of the model updates, this study also summarized the application trends such as integrated network design in strategic planning, synchronization and timetable recovery from disruption in tactical and operational planning. To improve the transit system and service, evaluation models on service reliability, service accessibility, timetable robustness, and energy consuming are proposed, which highlight the gap between the idealized service and the real service. Some flexible fare scheme, investments, and commercial strategies are discussed in the financial part. The conclusion highlighted the future scope of the smart urban transit in passenger demand management, travel information service, facility and service optimization and shared mobility, in order to make it more convenient for the passengers and more friendly to the environment.
Recently, automation, shared use, and electrification are viewed as the “three revolutions” in the future transportation sector, and the traditional scheduled public transit system will be greatly enhanced with flexible services and autonomous vehicle scheduling capabilities. Many emerging scheduled transportation applications include the fully automatic operation system in urban rail transit, joint line planning, and timetabling for high-speed rail as well as emerging self-driving vehicle dispatching. The vehicle routing problem (VRP) holds promise for seeking an optimal set of vehicle routes and schedules to meet customers’ requirements and plays a vital role in optimizing services for feature scheduled transportation systems. Due to the difficulty of finding optimal solutions for large-scale instances, enormous research efforts have been dedicated to developing efficient algorithms, while our paper presents a unique perspective based on a time-dependent and state-dependent path searching framework. An open-source and light-weight VRP with pickup and delivery with time windows (VRPPDTW) modeling package, namely VRPLite, has been developed in this research to provide a high-quality and computationally efficient solution engine for transportation on demand applications. This paper describes the space–time–state modeling process of VRPPDTW using a hyper-network representation. This solution framework can be embedded in a column generation or Lagrangian relaxation framework to handle many general applications. A number of illustrated examples are presented to demonstrate the effectiveness of the path search algorithm under various traffic conditions and passenger travel requirements.
It may be necessary to arrange railway traffic on the outer edge of the cantilever deck of a box girder bridge for the sake of transportation planning. A continuous box girder bridge was designed in China to carry a single-track urban rail transit traffic on the cantilever deck of the bridge and three-lane highway traffic on the other part of the deck. In order to investigate the possible resonant responses of the coupled train–bridge system, the resonance condition of the cantilever deck under moving train loads is discussed analytically, and then numerical analyses of the vertical train–bridge dynamic interaction considering local vibration of the cantilever decks are carried out. The degrees of freedom of the bridge modeled by shell elements are so large that mode superposition method is used to reduce the computation efforts. It is found that the resonance speed of the cantilever deck predicted by the analytical method is 305 km/h, which agrees well with the numerical result. The numerically computed results also indicate that the serviceability of the bridge deck and the ride quality of the railway vehicles in the vertical direction are in good condition below the critical speed of 200 km/h.
The need to financially support metro enterprises stems from the amplified global enthusiasm for sustainable modes of transport. This paper analyzes the formulation and practice of the profit model based on quasi-marketing initiated within Shenzhen Metro in China. In contrast to previous studies based on a single theory, this paper employs an integrated approach in optimizing gains. Metro enterprises have peculiar attributes such as supply of quasi-public service products, positive externalities, heavy assets, low profit, economy of scale, and economy of scope. Therefore, in order to effectuate sustainable growth, the author has put forward three methods for the profit model based on the quasi-market principle: firstly, generate internal gains of positive externalities through the enterprise’s market operation on government-allocated resources; secondly, balance cost and income by modifying the accounting policies on fixed assets depreciation and financing interest; and lastly, maximize economy of scope by enhancing synergy between different business segments and sub-businesses of the same segment in the enterprise. In practice, these methods are carried out in Shenzhen Metro with innovative methods that comprise “metro plus property”, “member plus fund” and “entity plus virtual”. This study concludes that the advantages of quasi-marketing include the optimization of resources and the success in overcoming the financial restraints in metro enterprises. Through the high applicability in Shenzhen Metro, it is shown that this quasi-market principle-based profit model could enable metro enterprises to achieve self-development and sustainability.