Coordination problems in container barging in the port of Rotterdam: an institutional analysis

Container barging has gained in importance in port-related transport along with the need for sustainable transport. Nevertheless, coordination problems between terminal operator and barge operator exist, and performance lags behind. This paper analyses factors that may hinder or stimulate a better future performance of container barging in the port of Rotterdam. A case study is accomplished and guided by a framework rooted in Institutional Economics. Despite favourable conditions set by governments and the port authority, the share of container barging has hardly grown. The container barging sector in Rotterdam is embedded in a history with many alliances, a high degree of organisation, and a good track record in the development of institutional arrangements to solve coordination problems. However, the present contractual relations in the transport chain form an inadequate condition. From a theoretical perspective, the paper shows the value of studying port-related transport chains by acknowledging their institutional context.     

Robust control of traffic networks under uncertain conditions

Uncertainty of traffic network operations has been a subject of lively debate in the last decade. However, little effort has been put in developing control frameworks that are not only aimed at improving the average performance of the system, but also at improving the system robustness and reliability. In fact, it can be argued that most of the current control approaches are only aimed at improving the efficiency, which can even be counterproductive from a robustness point of view. The main contributions of this article is the proposition of a new control framework based on the notion of controlled Markov processes, which explicitly takes into account the uncertainty in predicted traffic conditions and system performance. Furthermore, in contrast to traditional optimal control approaches, the objective function can include general statistic of the random system performance, such as the mean, standard deviation or 95‐percentile. The contribution aims to make clear how different performance function specifications yield different control strategies. This is shown for a relatively simple case study.     

铁道车辆液压减振器的工作原理和数值模型

基于液压减振器的工作原理、内部结构和阀元件的性能,建立了一个新的液压减振器数值模型。该数值模型不仅将阻尼力作为减振器活塞杆的速度与位移的函数,同时还含有用于描述内部结构的基本参量,可以清楚地描述液压减振器的阻尼机制。应用该模型可进行液压减振器的动态性能分析、结构设计、元件选用等。模型计算结果与实验数据有较好的符合性。该数值模型易于实现计算机数值仿真,可以应用于车辆系统动力学性能的研究和减振器的结构参数、动态性能对车辆舒适性和稳定性影响的深入分析。     

Empirical evidence on cruising for parking

The literature on car cruising is dominated by theory. We examine cruising for parking using a nation-wide random sample of car trips. We exclude employer-provided and residential parking. We focus on the Netherlands, where levels of on-street and off-street parking prices are locally the same. We demonstrate then that due to this price setting the average cruising time in the Netherlands is only 36 s per car trip. Furthermore, we show that cruising is not random. It is more common in (large) cities that receive more car trips, particularly for shopping and leisure activities. Cruising time increases with travel duration as well as with parking duration. Cruising has a distinctive pattern over the day with a peak in the morning, so the order of arrival is essential to parking. Because cruising has a spatial and time component, policies may be considered that reduce cruising time through flexible pricing of parking or improved information about vacant parking spaces.     

Link-level vulnerability indicators for real-world networks

It is computationally expensive to find out where vulnerable parts in a network are. In literature a variety of methods were introduced that use simple indicators (measured in real-life or calculated in a traffic simulator) to pre-determine the seriousness of the delays caused by the blocking of that link and thereafter perform a more detailed analysis. This article reviews the indicators proposed in the literature and assesses the quality of these indicators. Furthermore, a multi-linear fit of the indicators is made to find a better, combined, indicator to rank the links according to their vulnerability. The article shows that different indicators assess different links to be vulnerable. Also combined they cannot predict the vulnerability of a link. Therefore, it is concluded that to find vulnerable links, one has to look further than link-based indicators.     

Experimental investigation of the strength and stability of submarine pressure hulls with and without artificial corrosion damage

A submarine may have to operate for a period of time with local corrosion damage in the pressure hull if a suitable repair method is unavailable or too expensive for implementation. This paper describes collapse tests on twenty ring-stiffened aluminium cylinders, which were conducted to study the effect of corrosion damage on hull strength and stability. Artificial hull thinning was found to reduce the collapse strength of experimental models through high local stresses in the corroded region, leading to early onset of yielding and inelastic buckling. Bending associated with the eccentricity due to one-sided thinning was found to further increase the local stresses in the hull. Overall collapse pressures were more severely affected by corrosion damage than interframe collapse pressures. The percentage reduction in overall collapse pressure, compared with intact experimental models, was found to be closely related to the percentage depth of thinning. The accuracy of conventional collapse pressure predictions for the experimental models was significantly better for intact than for corroded cylinders.     

Modeling travel time reliability of freeways using risk assessment techniques

Travel time reliability is considered to be one of the key indicators for the performance of transport systems and is measured in various ways. This paper synthesizes both reliability concepts: traffic breakdown, the indicator of the instability of travel times, is treated as the risk, whereas travel time variability, the indicator of the uncertainty of travel times, is considered as the consequence of this risk. An analytical formula, using risk assessment technique, explicitly expresses the cost of travel time unreliability as the sum of the products of the consequences (i.e. variability) and the corresponding probabilities of breakdown. It provides a novel measure of travel time reliability and is applicable in network performance evaluations. An empirical example based on a large dataset of freeway traffic flow data from loop detectors shows that the developed travel time reliability measure is both intuitively logical and consistent.     

Risk and reward in public transport contracting

This paper synthesizes evidence from the workshop on risk and reward in public transport contracting. It broadens the usual risk/reward framework to encompass strategic/tactical level issues, identifying high level community goals as the ultimate risk/reward pay-off. The evolution of tactical level public transport planning is reviewed, noting considerable change in functional roles between purchaser and provider in some jurisdictions. No single “best” approach is evident but an emerging interest in relational contracting founded on trust is apparent. Risk allocation between purchaser and provider is considered, a key debate concerning the extent to which providers should be exposed to revenue risk.     

Coordination mechanisms in improving hinterland accessibility: empirical analysis in the port of Rotterdam

Hinterland accessibility is one of the main determinants in port competition. Improving hinterland accessibility is a complex process in which many actors are involved and many factors play a role. It requires coordination mechanisms beyond the price mechanism; conditions of complexity can become such that assistance is needed from other coordination mechanisms, such as introduction of incentives, creation of an interfirm alliance, changing scope, and creating collective action. The goal of this paper is to gain a better understanding on coordination in hinterland chains. Based on the insights of Transaction Cost Economics, a set of variables is explicated in order to understand when, by whom, and under which conditions and situations coordination arrangements are chosen. The variables can be divided into variables related to the complexity of the coordination problem and variables related to the coordination arrangement. The variables are used in an empirical analysis of coordination arrangements in hinterland transport from and to the port of Rotterdam. This analysis provides insight into the patterns and conditions of the emergence of different coordination arrangements that improve hinterland accessibility.     

Transportation education in the United States

Abstract

In the last decade the importance of attitude‐related residential self‐selection has frequently been recognized. In addition people can theoretically self‐select them with respect to other location choices, such as job locations, with respect to travel behaviour, or with respect to the exposure to transport externalities such as noise and congestion. In this paper, we argue that insights into self‐selection processes might significantly improve our knowledge on location choices, travel behaviour and transport externalities. We elaborate on options for self‐selection and briefly formulate methodologies for research into self‐selection.