Current publications

Despite the European Union (EU) efforts promoting policies that encourage short sea shipping (SSS) based on its advantages in terms of intermodality and environment, this mode has not yet reached a significant market share compared to land transport. In this paper, we establish a thesis that suggests that funding programs (such as Marco Polo I and II) have not properly offered the right incentives to promote SSS, and aspects such as the key role of port infrastructure and its characteristics, have not been taken into consideration. In a departure from traditional transport cost models, to prove our thesis, we use a theoretical intermodal competition model to compare alternative modes—road transport vs. SSS. We reach the conclusion that the EU needs to focus on ports and transport system efficiency as a whole in order to compete effectively in the freight transport market.     

The road network management system in Slovakia

Traffic on the road network in Slovakia is increasing greatly, as a result of the country's location in central Europe. In recent years, transit truck traffic has exceeded the network's capacity causing many accidents, low vehicle speed and rapid degradation of the pavement. To deal with this situation a Road Network Management System (RNMS) has been developed. This system is based on national standards that evaluate road parameters, characteristics, and traffic levels and on new methods that consider the environmental impact and methods based on international standards (HDM III). Using these, the RNMS was developed as one homogeneous unit, not only in terms of its capacity, traffic level and economic efficiency, but also to evaluate individual sections, to optimize action, and prepare a rehabilitation budget. It took only five years to develop the RNMS because Slovakia has much relevant experience based on high level research in highway design, structural pavement design and material engineering.     

布达佩斯停车管理中的TDM实践

中国目前的交通情况与过去的欧洲有很多相似之处,可借鉴其相关经验教训.以匈牙利布达佩斯为例,探讨其如何利用交通需求管理措施进行城市停车管理.首先指出停车管理的目标应为降低小汽车的使用需求、强化公共交通相对于私人交通的竞争力.然后,在路内停车管理层面,剖析中国停车管理存在的问题,分别从政策及标准、运营管理模式、技术应用三方...     

Optimal design and benefits of a short turning strategy for a bus corridor

We develop a short turning model using demand information from station to station within a single bus line-single period setting, aimed at increasing the service frequency on the more loaded sections to deal with spatial concentration of demand considering both operators’ and users’ costs. We find analytical expressions for optimal values of the design variables, namely frequencies (inside and outside the short cycle), capacity of vehicles and the position of the short turn limit stations. These expressions are used to analyze the influence of different parameters in the final solution. The design variables and the corresponding cost components for operators and users (waiting and in-vehicle times) are compared against an optimized normal operation scheme (single frequency). Applications on actual transit corridors exhibiting different demand profiles are conducted, calculating the optimal values for the design variables and the resulting benefits for each case. Results show the typical demand configurations that are better served using a short turn strategy.     

Designing robust rapid transit networks with alternative routes

The aim of this paper is to propose a model for the design of a robust rapid transit network. In this paper, a network is said to be robust when the effect of disruption on total trip coverage is minimized. The proposed model is constrained by three different kinds of flow conditions. These constraints will yield a network that provides several alternative routes for given origin–destination pairs, therefore increasing robustness. The paper includes computational experiments which show how the introduction of robustness influences network design. Copyright © 2010 John Wiley & Sons, Ltd.     

Willingness to pay for improving service quality in a multimodal area

Travellers use the installations at multimodal areas to transfer from one mode of transport to another. In many cases these installations are called interchanges. This article characterises the users of transport interchanges to determine the fundamental attributes which they most value when they pass through the area. A Stated Choice survey is designed and administered and Mixed Logit models are estimated to calculate willingness to pay levels for three main attributes: transfer time, the quality of the available information and the services provided in the area. Travellers place most value on the quality of the information they receive and the available services rather than on transfer time, which contradicts the widely held opinion of experts in the field. This opens up new possibilities in the design of modern interchanges which should concentrate more on being welcoming areas with many information points rather than being based around minimising transfer times.     

The link between traffic-related occurrence and annoyance

This paper examines the relationship between a respondent's estimate of a traffic-related occurrence and his/her level of annoyance with it. Factors such as traffic flow, speeding, parked cars, standard of the sidewalk, and cyclists on the sidewalk are tested. The data was collected in 2008 from a questionnaire study sent to circa 1400 residents living along four arterial streets in Malmö, Sweden. The results indicate that the respondents seem to associate the estimate of occurrence with a rather corresponding or lower level of annoyance. Deviations from these main results are mainly found for the oldest (> 64) age group where high estimate of occurrence is associated with low annoyance concerning some of the factors.     

应用于车辆实时动力学仿真的悬架模型

针对车辆动力学实时仿真的要求提出一种新的悬架建模方法。将悬架系统视为车身与车轮之间的无质量复合约束，利用悬架杆系的多体运动学模型和准动力学模型来分析悬架系统的运动和力学传动特性，从而悬架动力学问题简化为代数方程组的求解。与基于侧倾／力矩中心理论建立的等交悬架模型相比，该方法可分析悬架杆系内部作用力，并能更准确地描述悬架在水平方向的约束作用；与应用传统多体动力学理论建立的模型相比，该方法解决了仿真实时性的问题。基于这种方法建立了国产某轿车麦弗逊式悬架模型，并将仿真结果和道路试验及ADAMS仿真结果进行了对比，有较好的一致性。     

Overview of Coupling of Multibody and Control Engineering Tools

The role of Computer Aided Engineering in vehicle development has been significantly increased during the last decade. Specialised simulation tools became very complex, however, growing demands on complexity and particularly interdisciplinarity of vehicles and their simulation models have led to a number of approaches trying either to develop multidisciplinary simulation tools or to connect various specialised simulation tools by interfaces. This paper addresses some aspects of interconnection of the specialised simulation tools as one possibility for simulating complex mechatronic vehicle systems. It classifies the interfaces between specialised software packages in general, mentions some historical development of the interfacing and further discusses the examples of the implemented couplings between the Multibody System codes and Computer Aided Control Engineering tools. Finally, the performance of selected interfaces is compared on an example simulation of a controlled vehicle suspension.     

Influence of repeated and delayed excitations in combined subspace identification

The application of combined subspace identification methods to land vehicles would allow the modal parameters of the vehicle to be obtained, while it is in operation, thus improving the vehicle modal characterisation. However, when a land vehicle is circulating through a straight line, the excitations applied to the different axles are identical among them but with a certain time delay. The presence of repeated excitations with different time delays implies that the past and future subspaces include common vectors that may lead to problems in the application of the method. To analyse its influence, an index called the reduction coefficient resulting from excitations (RCE) has been defined. RCE evaluates the amount of information eliminated in the oblique projection due to the effect of repeated excitations. The use of RCE enables the selection of analysis parameters, particularly the sampling frequency, the signals grouping and some specific parameters of the subspace identification methods.