Personal Rapid Transit System Research Articles

Reducing the wasted transportation capacity of Personal Rapid Transit systems: An integrated model and multi-objective optimization approach

This study addresses the problem of wasted transportation capacity in Personal Rapid Transit (PRT) systems. We propose a two-tier transportation model that integrates PRT and capillary transportation systems. We study a related multi-objective empty vehicle redistribution problem that attempts to minimize empty movement and the number of vehicles used. Furthermore, we design a hybrid multi-objective genetic algorithm that integrates multiple crossover operators and linear programming techniques to solve the proposed problem. Evaluations indicate that our algorithm produces satisfactory results, and simulations confirm the efficiency of our proposed two-tier transportation system.

Discrete honeybee mating optimization algorithm for the routing of battery-operated automated guidance electric vehicles in personal rapid transit systems

Reducing the amount of energy consumed by mass transit systems can be a challenging task. The present study focuses on minimizing the energy consumed by a relatively new transportation system called a personal rapid transit (PRT) system. PRT systems provide automated direct nonstop transit services to their users. This study explores the routing problem associated with PRT where the aim is to minimize the energy consumption while considering the battery capacity of PRT vehicles. The honeybee mating optimization algorithm is adapted to this problem. A specific enhancement procedure is proposed that boosts the performance of algorithm based on a specific initialization of the population. A multiple-descendant honeybee mating optimization algorithm is also proposed. Finally, the algorithms were verified using a set of 1320 randomly generated instances and extensive statistical analyses were performed to validate the results obtained.

VNS as an upper bound for an exact method to solve a class of on-demand transit transportation systems

This paper considers the offline routing of a Personal Rapid Transit system. In particular, a branch and bound approach is combined with a variable neighborhood search, and this is adapted to the context of the problem as we introduce some linear programming techniques and different neighborhood operators to enhance its performance. Computational results show a good average gap between the lower and our method and this can be found in a relatively good computational time.

個別輸送システム合流部の時間制約による制御戦略

個別輸送システム合流部の時間制約による制御戦略

Preliminary economic appraisal of personal rapid transit (PRT) and urban gondola feeder systems serving a university campus and its surrounding major attractions

Personal rapid transit (PRT) and urban gondolas are two types of driverless transit vehicles that are increasingly attracting attention as viable mass transit alternatives in urban environments. Both systems are identified with high reliability of travel time, as they have their own right of way and, thus, do not interact with vehicular traffic. They are also associated with environmental benefits, resulting from their low emissions, energy use, and noise pollution. The objective of this study is the investigation of the potential economic viability of the implementation a PRT feeder line linking the University of Calgary to its surrounding major attraction centres, compared to that of two types of urban gondola systems. The main focus of the research is the examination of the thresholds and feasibility of these emerging urban transit systems relative to certain important inputs, such as capital costs, ridership levels, and modal shift from other modes. The VISSIM microsimulation tool was used to simulate the operation of these systems to replicate more closely the on-demand nature of PRT and to get better estimates of the operating speed, reliability, and passengers waiting, boarding and alighting times for both types of examined systems. The project efficiency was analyzed given the calculated economic cash flow for a certain period (e.g., 30 years). The results indicate that the three examined systems differed widely in terms of their capital cost, maintenance and operating cost, capacity, and their anticipated benefits.

Heathrow airport's personal rapid transit system proves to be a viable transport solution

This paper reports on the design, development and highly successful operation of the personal rapid transit system at London's Heathrow airport, UK. Over the past 3 years the 3·9 km ‘pod’ system has carried over a million passengers between Terminal 5 and its business car park. There are provisions in the structure to extend the system and plans have been developed for extension to Terminals 2 and 3. The light weight of the vehicles resulted in transport infrastructure with far lower weight, cost, visual intrusion and embodied energy than usual and required no highway or service diversions. Very high levels of operational effectiveness and reliability, together with an exceptionally positive response of passengers, suggest that personal rapid transit offers a valuable and viable new contribution to transportation.

PRT 차량의 보조 전력공급을 위한 유연소재 태양전지의 적용 가능성 연구

최근의 신 교통시스템 개발 동향은 주로 지속가능하고 친환경적인 교통수단을 제공하는데 초점이 맞춰져 있다. 그 중에서도, 수요응답형 순환교통(PRT: Personal Rapid Transit) 시스템은 그 가능성 때문에 주목을 받고 있으며, 첨단 전기 자동차(EV) 개발 기술과의 융합을 통해서 경쟁력은 보다 향상되고 있다. 하지만 전기 배터리에 의해 구동되는 차량의 경우 안정적이고 효율적인 운영의 측면에서 기술적인 어려움에 직면하고 있다. 본 논문에서는, 기술적인 난제를 극복하고 전기에너지를 기반으로 한 교통수단의 보급을 증대하기 위하여 태양전지에 의한 보조 전력 공급을 위한 설계적 접근방법에 대해서 모형실험을 통해서 논한다. 그 결과, 실제 차량에 적용했을 시 보조 전원 공급장치로서 일부 서비스 기기에 소요되는 전력량의 대략 11% 정도를 감당할 수 있을 것으로 예측되었다. 특히, 유연소재 태양전지의 장점은 저렴하고 가벼우며 디자인 의도를 최대한 살릴 수 있다는 데 있다. 무엇보다도 유연함과 용이한 부착성은 다양한 분야에서의 확대 적용 가능성을 보여준다. Recently, trends in new transportation system development have been primarily focused on sustainable and ecofriendly mobility solutions. The personal rapid transit (PRT) system has been considered a promising candidate in this category; its competitiveness is being improved through convergence with cutting-edge electric vehicle (EV) technologies. However, battery-powered vehicles pose difficult technical challenges in attempts to achieve reliable and efficient operation. In this study, a design approach for a solar-power assisted PRT system is presented with small-scale demonstrations aimed at circumventing challenges facing its adoption, as well as helping speed the transition to electric-powered ground transportation. From the results, it is expected that flexible photovoltaic (PV) cells will be able to supply 11% of the power required by the service equipment installed in a prototype vehicle. In particular, flexible photovoltaic (PV) cells are advantageous in terms of cost, weight, and design considerations. Most importantly, the cells' flexibility and attach-ability are expected to give them great potential for extended application in various areas.

Synchronous Routing for Personal Rapid Transit Pods

Personal rapid transit (PRT) is a public and automated transport system in which a fleet of small driverless vehicles operate in order to transport passengers between a set of stations through a network of guided ways. Each customer is carried from one station to another directly with no stop in intermediate stations. This mode of transport can result in a high level of unused capacity due to the empty moves of the vehicles. In this paper, we model the problem of minimizing the energy consumed by the PRT system while assuming predeterministic list of orders; then we solve it using some constructive heuristics. Experiments are run on 1320 randomly generated test problems with various sizes. Our algorithms are shown to give good results over large trip instances.

Minimising average passenger waiting time in personal rapid transit systems

Personal Rapid Transit (PRT) is an emerging urban transport mode. A PRT system operates much like a conventional hackney taxi system, except that the vehicles are driven by computer (no human driver) between stations in a dedicated network of guideways. The world’s first two PRT systems began operating in 2010 and 2011. In both PRT and taxi systems, passengers request immediate service; they do not book ahead. Perfect information about future requests is therefore not available, but statistical information about future requests is available from historical data. If the system does not use this statistical information to position empty vehicles in anticipation of future requests, long passenger waiting times result, which makes the system less attractive to passengers, but using it gives rise to a difficult stochastic optimisation problem. This paper develops three lower bounds on achievable mean passenger waiting time, one based on queuing theory, one based on the static problem, in which it is assumed that perfect information is available, and one based on a Markov Decision Process model. An evaluation of these lower bounds, together with a practical heuristic developed previously, in simulation shows that these lower bounds can often be nearly attained, particularly when the fleet size is large. The results also show that low waiting times and high utilisation can be simultaneously obtained when the fleet size is large, which suggests important economies of scale.

Demand and Schedule Operation Mode for Personal Rapid Transit

The PRT (Personal Rapid Transit) system is a new transportation system in accordance with the requirements of the passengers. Although this PRT system was proposed a long time ago, it did not hold the limelight due to the several limitations in technology. However, the research and development has been active again recently thanks to the development in technology and the review on its applicability as the means of transportation linking to the urban transit system. Although most of these recent studies in relation to the PRT are focused on the hardware such as PRT vehicles or track structures, etc., the operational aspect of it is more important than that of any other means of public transportation. Therefore, among studies on operational aspect of this PRT system, this paper shows the result of study on technology in relation to the movement of vehicle to the station where it was called by the passenger through interface of the wayside control center with the vehicle control system in case where the passenger calls a vehicle at the station.

소형궤도차량(PRT) 차체의 설계사양 도출 및 구조강도 평가 연구

PRT(Personal Rapid Transit) system is a new transportation system which will meet increasing demands of traffic in Korea. It is also an environment-friendly transportation and automatically operated. For these reasons, researches on the PRT system are actively undergoing, but the PRT vehicles have different forms of subway, bus, etc. There are no design standards to evaluate structural integrity, yet. In this paper, Structural design specifications are derived, which are based on the performance test standard for EMU and the ASCE-APM standards. We also perform the static and fatigue analyses by FE simulation and suggest strategies to improve an initial structure design. In addition, we derived the design specifications for energy-absorbing structures to meet the conditions of the collision scenarios predefined from a view point of operation safety.

운행 중인 PRT 차량의 수직이송을 위한 장치 개발

수요응답형 순환교통시스템(Personal Rapid Transit: PRT)은 자동차에 버금가는 승객의 요구 대응성 및 최적경로 운행으로 인한 높은 효율성 등의 특징 때문에 미래형 신교통수단으로서 많은 주목을 받아 왔다. 하지만 수송 분담 능력(4~6명)에 비해 건설비가 많이 들어가고 기존에 운용되고 있는 타 대중교통시스템과의 역할 분담 문제 때문에 적용에 한계가 있는 것도 사실이다. 따라서 본 연구에서는 도시 내 유연한 운용과 타 교통수단과의 연계를 목적으로 PRT 차량을 위한 수직이송장치를 개발하였다. 기존의 물류 분야에서 많이 채택되고 있는 순환 컨베이어 방식을 응용하였으며, 특히 연속이송이 가능하며 사이클 타임이 적은 장점이 있다. 이와 더불어 1/10 스케일의 모형의 제작을 통하여 장치의 기술적인 운용 가능성을 확인하였으며, 이를 통해 구조적 안정성을 확보하기 위한 방안을 도출하였다. The Personal Rapid Transit(PRT) system has been highly interested in future transportation developments due to its on-demand and optimized door-to-door transport capability. However, the major impediments to the commercialization of PRT are the high cost for construction of infrastructures as opposed to the small transport capacity and difficulty in defining the role of PRT in building a balanced transportation system. In this study, the vertical transfer device for the PRT vehicle is developed to provide more flexible and better compatible urban mobility services between means of transportation, which is expected to meet particular demands in a particular environment. This apparatus was initially designed based on the basis of vertical circulating conveyors with steel chains, which is frequently used in logistics. Its advantages are capable of the non-stop loading and reduced head-way time. Most importantly, it was intensified by the additional idea to ensure the stable and reliable transfer of the PRT vehicle fully loaded with passengers. The 1/10-scale prototype was successfully tested to demonstrate a fundamental mechanism of vertical transfer and identify unexpected user requirements prior to a real manufacturing process.

PRT 차량하부 열부하 저감방안 도출 연구

Personal Rapid Transit (PRT) is the emerging personal transport vehicle operating on the loop automatically. The PRT system utilize the electrical power from super capacity or battery, it is important to manage the power or energy. In this regards, the management of high temperature occurred by the operation of system is significantly important to prevent from serious damage of component. In this study, we studied the adequate shape of underbody which can reduce the heat accumulation by pickup coil and condenser using natural air cooling. We suggested the additional air pathway, air inlet and flow separator to decrease the temperature of the heat source components. It was found that suggested system can decrease the temperature of PRT under body by 16% during the static mode and by 10% during the running mode at 30km/h. It is expected that the findings of this study will feed into final design of newly built Korean PRT vehicle.

자동 운전 PRT 차량의 무선 관제 기술 개발을 위한 가상 환경 기반 통합 시뮬레이터 개발

Personal Rapid Transit(PRT), which is one of the next generation convergence transport technology, PRT system requires operation technology for controlling diverse vehicles and dealing with a variety of abnormal driving situations on a large scale trackway structures in expected operational area more efficiently and reliably. Before developing PRT control technology, it is essential that multiple testing procedures stepwise with building small scale test-tracks and develop real unmanned-vehicles. However, it is expected that the experiments demand huge amount of time and physical cost. Thus, simulation in virtual environment is efficient to develop wireless based control technology for multiple PRT vehicles prior to building real-test environment. In this paper, we propose a VR-based integrated simulator which physics engine is applied so that it enables simulation of front-wheel-steering PRT system rather than simple rail track system. The proposed simulator is also developed that it can reflect geographical features, infrastructures and network topology of expected driving region.

Comparative Analysis of Personal Rapid Transit as an Urban Transportation Mode

Personal rapid transit (PRT) is a modern form of transportation that moves people directly from origin to destination. PRT commonly consists of four-person driverless pods that travel on grade-separate right-of-way at speeds of around 25 mph. Planned PRT systems, with the exception of a system under construction in Amritsar, India, are relatively simple systems that consist of only a few stations on a short route. The potential of PRT as a substitute for traditional medium or large-scale urban transit such as bus rapid transit, light rail transit, and modern streetcars was examined. The proposed Purple Line light rail project in the Maryland suburbs of Washington, D.C., was modeled as a PRT system with the BeamEd 1.3.2 simulation tool, although the Purple Line route and station locations were not optimized for PRT. PRT, bus rapid transit, and light rail transit versions of the Purple Line were compared with respect to costs, environmental effects, and system performance. Multiple sensitivity analyses were performed to assess the effect of certain simulation inputs on PRT system performance. Comparisons between the three alternative modes of the Purple Line favor PRT in total travel times and capital costs, an indication that PRT could be a viable option as a transportation mode in other urban environments. The risk of failure in the implementation of a new technology on a grand scale is the largest obstacle that hinders wider PRT implementation.

Proactive empty vehicle redistribution for personal rapid transit and taxis

The empty vehicle redistribution (EVR) problem is to decide when and where to move empty vehicles in a Personal Rapid Transit or taxi system. These decisions are made in real time by an EVR algorithm. A reactive EVR algorithm moves empty vehicles only in response to known requests; in contrast, a proactive EVR algorithm moves empty vehicles in anticipation of future requests. This paper describes two new proactive EVR algorithms, called sampling and voting (SV) and dynamic transportation problem (DTP), that move empty vehicles proactively based on demand estimates from historical data. It also develops methods for assessing the performance of EVR algorithms absolutely in terms of both throughput and passenger waiting times. In simulation tests, the proposed algorithms provide lower passenger waiting times than other algorithms in the literature, and proactive movement of empty vehicles significantly reduces waiting times, usually with a modest increase in empty vehicle travel.

An investigation into the station capacities for personal rapid transit systems

The introduction of personal rapid transit (PRT) systems has been widely discussed in the field of transportation research. However, there is no robust criterion to derive station capacities, which is the determinant of overall capacity for a PRT system. The present study has provided a methodology to rigorously compute the capacity for simple serial-berth PRT stations with a single platform by considering three decisive factors: the demand level of incoming cars and outgoing passengers, the station structure and the operation strategy. A micro-level simulator was developed to analyze and derive station capacities for various combinations of these factors. In particular, the relationship between the wave-off rate and the waiting time, the factors that represent the level of passenger service, was investigated in detail. The station structure, represented by the number of platform berths, input queue berths and output queue berths, was also taken into account. Although a sufficient number of berths were provided (11 platform berths, 11 output queue berths and more than 22 input queue berths), it was impossible to operate a PRT station at an acceptable service level for passengers when the total demand was high (2500 per hour). Even when the total demand was less than or equal to 2000 per hour, it turned out that a relatively large number of station berths is required to ensure the service level.

Virtual Cities in Urban Planning: The Uppsala Case Study

Gearing cities towards a path of sustainability is a daunting task. The urban models that we have come to accept during the 20th century need to be revisited, but change, even if welcomed in abstract, is usually met in reality with enormous resistance from the economic and political models that underlie our cities. Some of the most powerful tools for promoting change are those related to conceptualization and visualization. When considering urban plans that aren't just incremental improvements over what already exists, city officials, urban planners and the general public must be able to visualize not just the merits of those plans in isolation, but how they interact with all the infrastructure that already exists. This paper describes one such urban plan that has been under consideration in the city of Uppsala, Sweden, for the past 5 years: a solar-powered Personal Rapid Transit (PRT) system connecting the main train station to the Hospital and the University. The process of discussing the PRT system included the development of a virtual reality simulation of parts of the city. We report on the process and role of this virtual reality simulation.

미시적 시뮬레이션을 통한 PRT 정류장 용량분석

The introduction of Personal Rapid Transit (PRT) has been widely discussed in the Korean transportation research field. However, there is no robust criterion to derive the throughput of cars and passengers at PRT stations, which plays a primary role in determining the overall capacity of PRT systems. The present study provided a methodology to rigorously compute the capacity for simple-serial PRT stations with a single platform, considering three decisive factors, i.e., the demand level of incoming cars and outgoing passengers, the station structure, and the operation strategy. A micro-level simulator was developed for the analysis of station capacity. And, by using this, station capacities were presented for various combinations of the decisive factors. In particular, the relationship between capacity and station structure was investigated in detail. Station structure is represented by the numbers of platform berths, input queue berths, and output queue berths. Moreover, both waive rate and waiting time, which represent the level of passenger service, were taken into account when the station throughput was computed.

Modeling and optimization of transportation systems

I am pleased to write a short editorial for this special issue, which highlights several areas of strength of the Journal of Advanced Transportation such as public transport and airport systems, transportation planning, techniques of transport systems analysis, and multiobjective optimization of transport systems. The emerging area of evacuation planning is also represented. The issue coincidentally highlights the truly global nature of our authors, as well as the interest that we have in attracting outstanding senior as well as emerging authors. A sister special issue on transport and traffic networks will be edited by Co-Editor-in-Chief William Lam. The papers that have been selected for this special issue are “On the allocation of new lines in a competitive transit network with uncertain demand and scale economies” by Zhi-Chun Li, William H. K. Lam, and S. C. Wong; “Simulation-based analysis of personal rapid transit systems: service and energy performance assessment of the Masdar City PRT Case” by Katharina Mueller and Sgouris P. Sgouridis; “Model of personal attitudes towards transit service quality” by Khandker M. Nurul Habib, Lina Kattan, and Md. Tazul Islam; “IF-EM: an interval-parameter fuzzy linear programming model for environment-oriented evacuation planning under uncertainty” by Qian Tan, Guo H. Huang, Chaozhong Wu, and Yanpeng Cai; “Airport gate reassignments considering deterministic and stochastic flight departure/arrival times” by Shangyao Yan, Ching-Hui Tang, and Yu-Zhou Hou; and “Multiple objective optimization of the fleet sizing problem for road freight transportation” by Jacek Żak, Adam Redmer, and Piotr Sawicki. Li et al. consider an innovative model for allocating new transit lines in a competitive network with demand uncertainty and scale economies. They explicitly consider interactions among the transit authority, transit operators, and transit passengers. Mueller and Sgouridis consider a zero-emission model city that is implementing a personal rapid transit system. The PRT will run throughout the city on an underground network. A discrete-event simulation model that supports the design and implementation of the system is described. Habib et al. present an investigation of the reasons for the use of transit in Calgary, Canada. The reasons are expressed as functions of people's perceptions and attitudes towards transit service quality. A multinomial logit model is developed to capture unobservable latent variables useful in defining passenger perceptions and attitudes. Tan et al. consider uncertainty related to factors involved in evacuation activities. The paper employs inexact optimization techniques to address the uncertainties. An interval-parameter fuzzy model is developed for evacuation management under uncertainty. Yan et al. develop an airport gate reassignment model that considers both deterministic (near future) and stochastic (later) flight departure/arrival times. An integer programming technique is applied to formulate a gate reassignment model (GRM). Because gate reassignment needs to be done repeatedly, the GRM is applied within a dynamic gate reassignment framework. Żak et al. consider a fleet sizing problem in a road freight transportation company with a heterogeneous fleet as well as technical back-up facilities. The decision problem is formulated in terms of multiple objective mathematical programming based on queuing theory. Various technical and economic criteria and stakeholder interests are taken into account.