Hierarchical multimodal hub location problem with time-definite deliveries

Hierarchical multimodal hub location problem is a cost-minimizing hub covering problem where two types of hubs and hub links, accounting for ground and air transportation, are to be established, while ensuring time-definite deliveries. We propose a mixed-integer programming formulation and perform a comprehensive sensitivity analysis on the Turkish network. We show that the locations of airport hubs are less sensitive to the cost parameters compared to the locations of ground hubs and it is possible to improve the service quality at not much additional cost in the resulting multimodal networks. Our methodology provides the means for a detailed trade-off analysis.     

Location analysis for the modal shift of palletized building materials

At present, the distribution of palletized building materials is mostly carried out by trucks, despite their movements having negative effects on society, the economy and the environment. However, these problems can be reduced if the transport of palletized goods is shifted to inland waterways. By doing so, the goods are bundled for the main haulage by barge. In order to reduce the transport distances by truck to an absolute minimum, a possible last-mile distribution would have to be organized via a limited number of directly canal-served hubs. The locations of those hubs are crucial for the feasibility of modal shift. This study advances the transport geography literature by elaborating a location analysis model specifically for palletized goods. This model determines the optimal hub location by taking into account the large variation of origins and destinations of transport flows, while the introduction of a cost structure enables potential economic gains (cost savings) and reductions in CO₂ emissions to be calculated. The analysis is performed for transport data on palletized building materials in Belgium. Two concepts were defined, which resulted in an optimal intermodal network of 9 hubs and one with 27 hubs; through the implementation of these networks, respectively 26% and 38% of the transport flows can be shifted to the inland waterways at a profitable cost. It can be expected that over time these percentages will increase further.     

Air freight hubs in the FedEx system: Analysis of fuel use

This paper provides a data based analysis of FedEx air freighter activities from selected hub locations. The basic idea is that air freighters have a set of range and payload parameters and their corresponding fuel burn depends on weight and distance. Data from 2011 to 12 (FlightAware) are used for 180,000 + flights on origin, destination and aircraft type. The particular aircraft vary widely in payload, but additional parameters may be derived from industry web sites and BTS. The research uses flight activity at hubs such as Memphis and Indianapolis (among others) and computes the aggregate distance flown on specific aircraft. The linkage between the hub and aggregate fuel use (assuming that the out bound flights are allocated to the hub) will give some quantifiable measures of the costs allocated to the hub. The paper examines particular aspects of the air freight system that are especially vulnerable to a spike in the costs of aviation fuel. These observations suggest that traffic to regional air express and air freight hubs is likely to respond in complex ways to fuel costs.     

Improving rural accessibility by locating multimodal mobility hubs

In rural regions, public transportation is often characterized by low accessibility as well as long waiting and travel times. In order to improve rural transportation systems, public decision-makers intend to implement alternative on-demand mobility modes. Herein, new intermodal travel itineraries with transfers at multimodal mobility hubs may enable faster public connections and thereby strengthen public transportation. Against this background, we present a decision support tool for locating multimodal mobility hubs to improve intermodal accessibility. As objectives, we aim at maximizing accessibility to workplaces and to places of private need. Our model decides on locations of multimodal mobility hubs and on the available on-demand mobility modes offered in addition to existing public transportation. We develop our model in an agile process together with rural decision-makers in the district of Heinsberg, Germany, and apply it in a real-world case study. As input for our model, we account for the existing public transportation system, identify points-of-interest, and estimate commuting volumes to workplaces based on official commuting data. Results promise a high potential to improve accessibility in rural areas. However, most of the improvement stems from unimodal car sharing trips.     

Improving interchanges in China: the experiential phenomenon

This paper examines the development of multimodal passenger rail hubs as part of the high-speed rail (HSR) network in the People’s Republic of China (PRC). The instrumental, attitudinal and affective experience of the journey through the interchange is assessed from the user perspective. Surveys are used from three HSR stations: Beijing South, Chengdu East and Suzhou North (N = 150), representing three types of HSR stations, i.e. national capital, regional capital and sub-regional city. ‘Expected’ and ‘realised’ facilities are compared – with the difference representing the ‘disgruntlement’ factor (after Stradling et al., 2007).The unprecedented urbanisation process currently being witnessed in the PRC, together with the rapid development of the HSR network and associated multimodal interchanges, offers much opportunity to develop a leading-edge public transport system and urban development predicated on the use of public transport. Although the importance of intermodal interchange hubs is being increasingly recognised, the journey experience through the interchange often remains poor, with problems including Wi-Fi availability, waiting and seating, the availability of door-to-door ticketing, crowdedness, access to the hub, time of travel through and waiting in the hub. MANOVA analysis and factorial (three way) MANOVA analysis are used to explore the differences between intermodal hubs, with many instrumental and particularly attitudinal and affective factors being significantly influenced by location.     

Analyzing the impact of intermodal-related risk to the design and management of biofuel supply chain

This study presents a mathematical model that designs a reliable multi-modal transportation network for a biofuel supply chain system, where intermodal hubs are subject to site-dependent probabilistic disruptions. The disruption probabilities of intermodal hubs are estimated by using a probabilistic model which is developed using real world data. We developed an accelerated Benders decomposition algorithm to solve this challenging NP-hard problem. Numerical analysis show that the model selects to use intermodal hubs located in areas with low disruption probabilities. In case of a disaster, the reliable solution results in 6.21% savings over the minimum cost solution.     

Hub premiums in European civil aviation

We investigate the practice of carriers that charge higher fares for flights leaving from their hub. We analyze this phenomenon by relating fares to distance, using the main leg of intercontinental flights for scaling purposes. Our results indicate that the practice of a mark up on flights originating from or going to hubs is not typical for the US situation. At least some European carriers charge significant premiums for direct flights from their hubs. We find that at least part of these premiums can be attributed to market power. Policy measures should be aimed at reduction of market power and consumer protection. Furthermore, the existence of hub premiums should be taken into account in regional hub policies.     

石衡沧港城际铁路互联互通方案研究

突出功能定位,发挥路网互联互通作用,是高速铁路互联互通方案研究的关键。在阐述石衡沧港城际铁路互联互通现状的基础上,针对石衡沧港城际铁路客流特点和功能定位,分析石衡沧港城际铁路石家庄铁路枢纽、衡水铁路枢纽、沧州铁路枢纽和黄骅铁路枢纽等互联互通主要节点枢纽,通过衡水、沧州和黄骅铁路枢纽比选方案分析,提出石衡沧港城际铁路在通道中的枢纽方案,为区域连接线、城际铁路在方案互联互通作用提供研究支撑。     

Hub competition and travel times in the world-wide airport network

The aim of this work is to measure the competition between airport hubs based on an analysis of travel times in the world-wide airport network. By considering the minimum travel time required to connect each pair of airports, it is possible to create new measures of hub competition, separating the effects of hub position and temporal coordination. This analysis was carried out at the global level, considering all 232 airports with more than 3 million seats yearly offered in departure flights in 2008, and also in relevant geographic markets. The results show a high level of competition among the most important world airports, but the major airports of Europe have a geographical advantage in relation to world markets over the major American and Asian airports. We also show that airports located in different continents often compete for the same origin–destination markets. Geographical position appears to be the most important variable explaining hub performance. Secondary hubs show a higher degree of specialization towards specific markets.     

An economic–geographic assessment of the potential for a new air transport hub in post-Gaddafi Libya

Post-war Libya is faced with the challenge of adopting an air transport strategy for the future. One issue is how to address projects inaugurated under the Gaddafi government, such as the terminal extension at Tripoli International Airport. Additionally, the state-owned Afriqiyah Airlines had been establishing a niche hub in Tripoli before the 2011 war, but this development has subsequently been stalled.Against this background, we analyse the prospects of an air transport hub operation in Libya, focusing on traffic between Africa and Europe, from a bird’s-eye economic–geographic view. First, a literature review is undertaken to identify general success factors for air transport hubs. Second, a weighted average distance penalty (WADP) indicator is developed and applied to Tripoli as a potential hub location. This indicator considers all 4755 O&Ds between Europe and Africa with more than 100 passengers in 2012. For sensitivity reasons, alternative WADPs are estimated for the 3209 traffic flows not including North Africa and for (forecasted) future air traffic demand in 2020. The results for Tripoli International Airport are benchmarked against competing hub locations, such as Algiers, Cairo, and the major European airports. We conclude by discussing the implications of the current and anticipated future security and economic situation in the country.     

综合客运枢纽框架性行业规范和标准体系研究

综合客运枢纽是经济社会发展到高级阶段的产物，对综合化水平提出了更高要求。在分析综合客运枢纽圈层形态基础上，认为规范标准体系是一系列技术性、政策性和制度性文件的综合反映，承担了法律规范、规划体制、技术标准等综合功能。在总结境内外经验基础上，认为我国综合客运枢纽规范标准需要考虑10大基准元素，构建出由60个指标构成的框架性体系。     

Intermodal routing of Canada–Mexico shipments under NAFTA

This paper obtains the optimal routings for intermodal containerized transport from Canada to Mexico. Such traffic is being stimulated by the North American Free Trade Agreement (NAFTA), but the cost and lead times of feasible routes are not well known. We summarize the links and routes to Mexico on which one or more carriers now operate, and then determine non-dominated tradeoffs between cost and service. Every southbound route from Canada requires a transshipment point in the southern or southwestern U. S. Feasible transshipment points are also candidate locations for a manufacturing ‘twin plant’, a distribution centre, or a transportation hub. Here, as a first step in this bigger problem, a network is constructed between five Canadian origins and three important Mexican destinations. Each link employs available intermodal services whose transit time and transportation cost are obtained through industry sources. A shortest-path algorithm enables calculation of the route requiring least time and the route of minimum cost. Non-dominated time/cost tradeoffs are identified for each origin–destination pair. After including inventory expenses (by parametrizing the unit value of lead time), total-cost curves then eliminate some routing alternatives. Guidelines are provided on the effects of mode, carrier, and O–D locations on selection of intermodal routes to Mexico. Finally, two new intermodal services are proposed and their benefits discussed.     

Long-haul specialization patterns in European multihub airline networks – An exploratory analysis

Multihub airline networks are an important phenomenon in today's air transport market. An important question is to what extent different factors play a role in the specialization between hubs that are part of the same multihub network. This paper shows that total European market size to a certain long-haul destination and the ratio between the origin-destination market at the primary and the secondary hub are important variables for the role hubs play in the long-haul network of European multihub systems. Large long-haul markets are generally served from both the primary and secondary hub. Multihub carriers serve smaller long-haul markets uniquely from a single hub, depending on the relative advantage in the local origin-destination market. Looking at actual specialization patterns within European multihub networks, we distinguish between complementary multihub systems (such as Amsterdam–Paris CDG), overflow systems (such as Frankfurt–Munich) and regional systems (such as Paris CDG–Lyon).     

Fair profit contract for a carrier collaboration framework in a green hub network under soft time-windows: Dual lexicographic max–min approach

This paper models a novel and practical bi-objective hub-location problem under a centralized carrier collaboration framework between one holding company and multiple carriers. The holding company first establishes a hub-and-spoke network in order to locate p hubs and to assign the center nodes to the located hubs. Then, it allocates the transportation routes of the hub network to the carriers. In contrast, the carriers should select an appropriate vehicle type to serve the transportation requests in a green hub network. The carriers are also able to meet the transportation requests within a certain time-window based on a soft time-window mechanism. Moreover, aiming to emphasize green transportation, a vehicle emission model is used to take into account CO₂ emissions of the vehicles where the fuel consumption is a function of speed level. Aiming to identify a win–win deal between the holding company and the carriers, a dual lexicographic max–min (LMM) approach is used in order to optimize their profits in a fair way. Finally, some numerical experiments are presented to demonstrate the applicability of the proposed methodology. The computational results show that not only the holding company and the carriers can better generate a fair profit contract among themselves using the LMM approach, but also both can obtain more profit in the worst case for their businesses rather than using the max–min approach. In addition, sensitivity analyses show that increasing the size of the soft time-window leads to a reduction in the delivery schedule violations, while results in raising the total profit. Moreover, the tax cost of fuel consumption as well as the number of potential vehicles has a substantial impact on both the fuel consumption and carrier’s profit.     

综合客运交通枢纽分类分级研究

在分析现有研究的基础上,结合城市交通特性和综合客运交通枢纽发展方向,对综合客运交通枢纽定义、分类、分级和规模等问题进行探讨。梳理目前枢纽建设所面临的问题,结合未来城市建设重点以及城市部分功能的调整情况,理清枢纽建设与上述问题之间的内在联系,探讨枢纽的功能定位、分类、分级等问题,为今后综合客运交通枢纽规划建设提供技术支撑,实现不同区域综合客运交通枢纽的差别化布局和规划,促进综合客运交通枢纽系统、区域交通一体化以及社会经济的全面发展。     

铁路交通枢纽与城市综合体设计初探

通过对国内铁路旅客车站交通枢纽设计模式及国外交通枢纽城市综合体典型案例的分析和总结．提出铁路旅客车站结合物业开发设计并形成交通枢纽城市综合体将是国内铁路旅客车站发展趋势之一的观点,以期对今后铁路旅客车站的建筑设计有所启示。     

Determining passenger potential for a regional airline hub at Canberra International Airport

This study investigates the implications on passenger flows of a regional airline adding a hub to its existing network. The very specific application focuses on a hub addition at Canberra International Airport (Australia) by Hazelton Airlines, although the approach is sufficiently general to implement for other hubs and regional airlines.     

杭州东站综合交通枢纽规划设计的思考

杭州东站综合交通枢纽规划设计对全国同类型的综合交通枢纽建设具有较强指导和借鉴价值。从综合交通枢纽的概念入手，结合当前综合交通枢纽的发展形势与背景，在文献研究和实践调研的基础上，介绍了杭州东站综合交通枢纽设计研究概况。对杭州东站综合交通枢纽的规划、设计和建筑特点等进行分析和思考，就如何建设好我国未来铁路综合交通枢纽，使之在规划设计、功能布局等方面与城市融为一体，实现交通功能和城市功能的和谐发展等提出了相应的建议。     

What hurts the dominant airlines at hub airports?

This paper estimates a frequency equation to explain the determinants of network airline service levels at their hub airports. Drawing on European data for 2002–2013, we find that network airlines reduce frequencies when the share of low-cost airlines increases both on the route and at the hub airport. On the contrary, frequency choices of network airlines are not affected by competition from low-cost airlines operating in nearby secondary airports. We also find some evidence that mergers in Europe may result in a re-organization of the route structure in favor of the hubs of the larger airline.     

Robust hub network design problem

This paper presents a robust formulation for the uncapacitated single and multiple allocation hub location problem where demand is uncertain and its distribution is not fully specified. The proposed robust model is formulated as a mixed integer nonlinear program and then transformed into a mixed integer conic quadratic program. An efficient linear relaxation strategy is proposed which is found to deliver the optimal solutions for all the cases considered in this paper. Numerical experiments suggest location of more number of hubs when accounting for demand uncertainty using robust optimization compared to the deterministic setting.