This paper deals with the measurement of the network complexity of some selected shipping groups, also identifying the contribution of co-operative agreements among carriers. The empirical investigation is focused on: (i) the analysis of the distribution of the carrying capacity per range; and (ii) the comparison of that capacity with the throughput handled in the port facilities of the group. These variables are interpreted in the light of the impact that alliances have on the geographical wideness of the services supplied by each partner. This factor also allows to depict how the cultural and political origin of shipping lines affects the decision of joining an alliance and the outcomes deriving from such co-operation. 相似文献
Transportation - The Netherlands seems to exhibit the unique conditions that allow cycling on the country level instead of only the city level. Moreover, the national transit system seemingly... 相似文献
Transportation - Urban utility cycling is being promoted widely due to various health, social, economic and environmental benefits. This study seeks to identify and rank which municipal-level... 相似文献
There is broad and growing consensus regarding the central place of integrated Land Use and Transport (LUT) strategy development
in establishing more efficient and sustainable urban environments. However, empirical evidence shows that such integration
is hard to achieve in daily planning practice, due to many institutional barriers and substantive differences. More specifically,
the tools developed to support LUT strategy development have very low implementation rates in daily planning practice. This
paper introduces the concept of ‘knowledge generation’ as a potentially useful mechanism for closing the gap between support
tools and planning practice. Through two specific Dutch planning cases, we analyze the applicability of this concept in supporting
integrated LUT strategy development. The paper focuses on the developed strategies, how these differ from current practice,
and how knowledge generation supported their development. We argue that socialization produces shared strategies and that
effective socialization needs to be supported by efficient mutual exchange between tacit and explicit knowledge. We conclude
by discussing the implications of this argument for the wider practice of LUT planning integration. 相似文献
The importance of measuring customer satisfaction for a public transport service is apparent, even beyond more immediate marketing purposes. The present paper shows how satisfaction measures can be exploited to gain insights on the relationship between personal attitudes, transit use and urban context. We consider nine satisfaction measures of urban transit services, as expressed by a representative sample of Italian multimodal travelers (i.e. users of both private cars and public transport). We use correlations and correspondence analyses to show if and how each attribute is related to the levels of use of public transport, and how the relationship is affected by the urban context. Then we apply a recently developed method to combine ordinal variables into one score, by adapting it to work with large samples and with satisfaction measures which have a neutral point in the scale (i.e. “neither satisfied nor dissatisfied”). The resulting overall satisfaction levels and frequency of use were not correlated in our sample. We also found the highest satisfaction levels in smaller towns and the lowest ones in metropolitan cities. Since we focus on multimodal travelers, an interpretation paradigm is proposed according to which transit services must be well evaluated by car drivers in smaller towns in order to be considered a real alternative to cars. On the other hand, transit is more competitive on factual elements in larger cities, so that it can still be used by drivers, even if it is not very well evaluated. 相似文献
Market segmentation studies in travel behavior research are ordinarily based on socioeconomic characteristics and personality
traits. This study explores the usefulness of a different approach, where the actual overall mobility levels across different
ground transportation modes, along with desired changes in the use of cars and transit, are used as clustering variables.
Using a given mode can in fact influence the personal representation of that mode, which in turn has been proven to be a key
element in transport behaviours. We form such multimodality-based clusters from two field studies, one involving employees
of the French transportation research institute INRETS and the other a representative sample of residents of the US San Francisco
Bay Area. We find that strong users of a given mode would like to bring more balance to their “modal consumptions” by decreasing
the use of this mode more than the average, and increasing the use of the alternative mode. However, concerning ground transport
travel budgets, the desire to travel more (or less) overall seems less strongly related to the composition of the modal balance. The US dataset shows also a greater latent demand for
travel than the French one. Socioeconomic characteristics of the clusters could not explain the patterns that were found,
confirming the importance of taking into account multimodality issues in travel behavior research. Some policy implications
from these findings are finally reported.
Ordinal measures are frequently encountered in travel behavior research. This paper presents a new method for combining them
when a hierarchical structure of the data can be presumed. This method is applied to study the subjective assessment of the
amount of travel by different transportation modes among a group of French clerical workers, along with the desire to increase
or decrease the use of such modes. Some advantages of this approach over traditional data reduction technique such as factor
analysis when applied to ordinal data are then illustrated. In this study, combining evidence from several variables sheds
light on the observed moderately negative relationship between the personal assessment of the amount of travel and the desire
to increase or decrease it, thus integrating previous partial (univariate) results. We find a latent demand for travel, thus
contributing to clarify the behavioral mechanisms behind the induced traffic phenomenon. Categorizing the above relationship
by transportation mode shows a desire for a less environmental-friendly mix of modes (i.e., a greater desire to use heavy
motorized modes and a lower desire to use two-wheeled modes), whenever the respondents do not feel to travel extensively.
This result, combined with previous theoretical investigations concerning the determinants of the desire to alter trips consumption
levels, shows the importance of making people aware of how much they travel.
Knut M. WittkowskiEmail:
Marco Diana
is a permanent researcher working at the Department of Hydraulics, Transport and Civil Infrastructures of Politecnico di Torino,
Italy. His research interests include the study of innovative forms of public transport services and the analysis of multimodality
behaviors.
Tingting Song
is a Scientific Programmer at The Rockefeller University, Center for Clinical and Translational Science, Biostatistics, Epidemiology,
and Research Design Core, New York, NY, USA. She works on algorithms for non-parametric methods and their applications in
medical research. She maintains the muStat package on CRAN.r-project.org and the Web server on muStat.rockefeller.edu.
Knut M. Wittkowski
is a Senior Research Associate at The Rockefeller University and Head of Biostatistics, Epidemiology, and Research Design
at its Center for Clinical and Translational Science, New York, NY, USA. His research focuses on methods, meta data, and user
interfaces to integrate nonparametric statistics into research and decision support systems. 相似文献
Transportation - The combined use of the bicycle and the train in the Netherlands has risen steadily over the past decade. However, little is yet known about the underlying processes driving the... 相似文献
This study examined whether interactions between travel mode attitudes, urbanization level, and socio-demographics were different for bicycle commuting and cycling for other purposes. Data were obtained from the 2014 wave of the Netherlands mobility panel (MPN). In total, 2673 respondents (18?+?years) who had recorded at least one trip on the days covered by the survey were included in the sample. Four outcomes were constructed, two of which concerned commuting-related cycling: any commuting-related bicycle usage (yes vs. no) and average cycling duration (in hours per weekday). Likewise, two similar outcome variables concerning cycling for other proposes were constructed. These outcomes were analyzed by means of Tobit regression models (cycling duration) and binary logistic models (any bicycle usage). Attitudinal factors concerning different travel modes, namely bus, car, cycling, and train, were constructed by means of factor analysis. The results showed that a positive attitude toward cycling was positively related to bicycle commuting duration, but this association was less strong among those with a positive attitude toward bus use. Having a positive cycling attitude had a weaker association with both bicycle commuting usage and duration in those who do not always have a car available. Regarding cycling for other purposes, cycling attitude had a stronger positive association with cycling duration among residents of very highly urbanized area, compared to residents of less urbanized areas. The available evidence, though limited, suggests that targeting attitudes can have a measurable impact on bicycling, but not to the same extend among all people.
Race car performance is strongly affected by aerodynamics. Due to downforce generated by the vehicle floor (i.e. diffuser), vehicle ride heights are key parameters to improve performance, and the coupling of aerodynamics and suspension is one of the key points of race car setting. This work focuses on the suspension and aerodynamic coupling from the vertical dynamics point of view. Besides road holding performance, for race cars, aerodynamic performance and stability are major factors. Downforce decreases laptime (the main performance target) but pitch instability is a non-desired effect that can happen in high downforce race cars. A new vertical dynamic performance index is proposed through the use of simulation to improve aerodynamic performance and understand the pitch instability phenomenon. This new index uses all relevant vehicle nonlinearities related to vertical dynamics and can handle a specific track profile and vehicle speed range, allowing the analysis be conducted according to a circuit specification. A previously validated Formula 3 car model was used as an example. 相似文献