Hierarchical system of road networks with inward, outward, and through traffic

This paper formulates a continuous model of a grid road network for determining the optimal hierarchical system of road networks. The hierarchical system is represented as the proportions of area taken up by roads at each level of the hierarchy. The objective is to derive the optimal ratio of road areas that minimizes the total travel time. The model explicitly incorporates inward, outward, and through traffic as well as inner traffic to examine how traffic composition affects the optimal ratio of road areas. The result reveals that the optimal ratio of major arterial roads increases with inward, outward and through traffic.     

Short haul business travel in the European Union: a segmentation profile

Business travellers tend to be charged a premium for the air services they consume due to the nature of demand, and therefore represent a potentially high source of revenue to airlines. Airlines are keen to secure and maintain executive travel business. The research investigates the short haul business air travel market in Europe, using a conceptual benefit segmentation model that addresses the industrial nature of the market. Three distinct market segments are identified; the schedule driven segment, the corporate cog segment, and the informed budgeter segment. A profile of these market groupings is given and implications for marketing strategy discussed.     

Connectivity analysis of transshipments at a cargo hub airport

The paper investigates the interconnectivity of airfreight networks as temporal concentrations at airport. The connectivity of freight transshipments depends on both the quality of connections at hub airports and the quality of indirect flights compared to direct flights. Here connectivity of flight schedules is analyzed using a temporal wave structure to estimate the degrees of connectivity and the quality of connectivity.     

Travel time use and its impact on high-speed-railway passengers' travel satisfaction in the e-society

The availability of wireless networks and the pervasive use of mobile ICT devices have allowed passengers to conduct various e-activities during journeys. These various e-activities, in turn, may change people's conventional perception of travel time from being “wasteful” and “unproductive,” to “desirable” and giving rise to satisfaction. Journeys on high-speed railway (HSR) is particularly relevant for transport researchers to probe into this question because of its characteristics of being medium to long-distance (typically taking half-an-hour or more), seat availability, and a smooth ride. Using a questionnaire survey on passengers along the Shanghai-Nanjing HSR route, this study aims to examine the nature of ICT device use and in-vehicle e-activities conducted by HSR passengers and the influence on their travel satisfaction with their on-board journey experience. Our results reveal a high percentage of ICT device use and a wide variety of e-activities such as e-working, e-communication, and e-reading for leisure on HSR trains. In addition, the higher use of ICT device was associated with an increase of passengers' travel satisfaction. Furthermore, we found a positive effect of work-related e-activities on travel satisfaction for business/work trips, while a positive effect of entertainment-related e-activities for non-business/work trips. Given that HSR is potentially a more sustainable transport mode, some possible policy implications are proposed to encourage people to use HSR, as opposed to driving or flying, for medium to long-distance intercity journeys.     

Do people consider an acceptable travel time? Evidence from Berkeley,CA

This paper explores the extent to which people identify an acceptable travel time for each trip they want to make and investigates the primary characteristics of this behavioural threshold. We assume that an acceptable travel time is defined through utilitarian processes that are related to cognitive and affective evaluations of travel that develop throughout a person’s lifetime. We apply a mixed methods approach to explore our hypothesis, based on semi-structured in-depth interviews with a stratified, according to commuting mode, random sample of 20 individuals living in Berkeley, CA. Our results support the validity of the acceptable travel time concept and offer (a) initial evidence on its variation to the travel mode and sociodemographic characteristics and (b) insights into people’s perceptions, attitudes, feelings and experiences about their travel. Thus, our results can contribute to a better understanding of individuals’ travel decisions and valuation of travel time and can inform time–space and accessibility research.     

Algebraic connectivity maximization of an air transportation network: The flight routes’ addition/deletion problem

A common metric to measure the robustness of a network is its algebraic connectivity. This paper introduces the flight routes addition/deletion problem and compares three different methods to analyze and optimize the algebraic connectivity of the air transportation network. The Modified Greedy Perturbation algorithm (MGP) provides a local optimum in an efficient iterative manner. The Weighted Tabu Search (WTS) is developed for the flight routes addition/deletion problem to offer a better optimal solution with longer computation time. The relaxed semidefinite programming (SDP) is used to set a performance upper bound and then three rounding techniques are applied to obtain feasible solutions. The simulation results show the trade-off among the Modified Greedy Perturbation, Weighted Tabu Search and relaxed SDP, with which we can decide the appropriate algorithm to adopt for maximizing the algebraic connectivity of the air transportation networks of different sizes. Finally a real air transportation network of Virgin America is investigated.     

Valuation of travel time for international long-distance travel – results from the Fehmarn Belt stated choice experiment

The geographical scope of travel varies from short distances in urban areas to long distances across cities and countries. While urban travel has been widely analysed in the literature, travel over longer distances and particularly across countries, has received much less attention. While this may be justified due to the number of travellers it cannot be justified when looking at the mileage consumption and its resulting environmental impacts. In this paper, we investigate international long-distance travel preferences related to travel between Scandinavia and Central Europe with particular focus on the Fehmarn Belt fixed link between Germany and Denmark to be opened in 2021. To facilitate long-term demand forecasts for the future fixed link, stated preference data were collected in 2011. Based on these data a discrete choice model for long-distance travellers was developed in order to estimate the value of travel time savings (VTTS). The final model, which was formulated as a nested logit model and included Box–Cox transformed travel time and cost attributes, revealed several interesting findings. Firstly, we found damping effects in both cost and time – most strongly in cost. Secondly, we found significant interactions among travel cost and time, and journey characteristics, such as distance and duration. This had direct impact on the VTTS, which was shown to decrease with distance and duration. Thirdly, we found that air travel implies a higher average VTTS, which is to be expected but rarely supported by empirical evidence.     

基于总出行时间最少的城市轨道交通站问距探讨

车站站间距规划和设计是城市轨道交通规划与设计的重要内容。从社会扩大再生产的角度分析了把总出行时间最少作为目标函数的必要性,得出了基于总出行时间最少的最优站间距的计算方法,研究了各个因素变化对站间距的影响,得出的结论为实际工作中站间距的合理确定提供了理论支持。     

Travel-time reliability impacts on railway passenger demand: a revealed preference analysis

We study the impact of travel-time reliability on trips made by railway passengers. Unlike most of the studies in this area, which make use of stated preference survey data, we use a revealed preference data set obtained by measuring the railway reliability and the number of season-ticket holders on the Dutch railway network. We make use of six travel-time reliability indicators, including the standard deviation and the 80th minus the 50th percentile of travel time. Our results indicate that the 80th minus the 50th percentile indicator best explains the fluctuations in the number of season-ticket holders. A 10% improvement of this indicator results in a 1.47% increase in the number of season-ticket holders.     

The trilogy of distance, speed and time

Over the recent past there has been a dramatic increase in travel, mainly driven by the desire to move faster and over ever greater distances. This growth is unsustainable, and the continued growth in levels of mobility needs to be reassessed through substantially reducing the levels of consumption (energy and carbon) in transport. This means that travel activities should be based on shorter distances and slower speeds, with a more flexible interpretation of time constraints. Transport geographers should have a strong and instrumental role to play in this debate. This paper outlines the changing patterns of movement, before concentrating on urban areas where most daily travel takes place, and it examines the trilogy of distance, speed and time. The focus of the paper is on distance, and the role that land use planning and development, and technology can play in encouraging new forms of travel in cities, but there are strong implications on the ways in which speed and time are conceptualised. The conventional transport paradigm is heavily embedded in the belief that travel time needs to be minimised and consequently speeds need to be increased. The resulting impacts on travel distances have not been part of that debate, but reducing travel distances is central to sustainable transport.