Continuous Modeling for Design of a Shuttle System With Modular Vehicles
Dynamic capacity design holds a low-hanging opportunity to reduce the energy consumption of urban mass transit systems, e.g., urban rail transits, bus rapid transits, modular autonomous vehicles. In this paper, the authors investigate the joint design of dispatch headway and vehicle capacity for one to one shuttle systems with oversaturated traffic to achieve the optimal tradeoff between general vehicle dispatching cost (mainly comprised of vehicle energy consumption) and customer waiting cost. The authors propose a continuum approximation (CA) model from a macroscopic point of view to reveal fundamental analytical insights into the optimal design. By introducing the concept of a desired arrival demand curve, the authors prove that the investigated problem with possibly oversaturated traffic can be equivalently solved with a simpler revised problem where only unsaturated traffic is present. With this property, the authors decompose the original problem into a set of independent unit-time revised unsaturated problems that can be analytically solved in each neighborhood across the operational horizon. With extensive numerical experiments, the authors show that the CA model offers near-optimum solutions with negligible errors very efficiently and they also verify the theoretical properties. Also, the effectiveness of dynamic vehicle capacity design is demonstrated in shuttle systems under both saturated and unsaturated traffic. Overall, the proposed CA model contributes to the CA methodology literature by extending the CA method for traditional transit dispatching problems with unsaturated traffic to the joint design of dispatch headway and vehicle capacity considering oversaturated traffic, adjustable vehicle capacities and minimum dispatch headway.
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Supplemental Notes:
- This paper was sponsored by TRB committee ADB30 Standing Committee on Transportation Network Modeling.
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Corporate Authors:
Transportation Research Board
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Authors:
- Chen, Zhiwei
- Li, Xiaopeng
- Zhou, Xuesong
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Conference:
- Transportation Research Board 98th Annual Meeting
- Location: Washington DC, United States
- Date: 2019-1-13 to 2019-1-17
- Date: 2019
Language
- English
Media Info
- Media Type: Digital/other
- Features: Figures; References;
- Pagination: 6p
Subject/Index Terms
- TRT Terms: Approximation (Mathematics); Continuum (Mathematics); Dispatching; Energy consumption; Headways; Mathematical models; Modular structures; Optimization; Shuttle buses; Shuttle service; Vehicle capacity; Waiting time
- Uncontrolled Terms: Modular vehicles
- Subject Areas: Highways; Operations and Traffic Management; Planning and Forecasting; Public Transportation; Vehicles and Equipment;
Filing Info
- Accession Number: 01698238
- Record Type: Publication
- Report/Paper Numbers: 19-02322
- Files: TRIS, TRB, ATRI
- Created Date: Mar 1 2019 3:51PM