Congestion is the natural consequence of intensive use of a road network in developed urban areas and is among the most critical negative factors affecting urban quality of life. There are several types of congestion, but the real damage is done by recurrent congestion during rush hours. Road networks with recurrent congestion are found in urban-suburban areas where the traffic volume is high enough and the road network is sufficiently dense to speak of network congestion. This congestion is caused by urban growth and long-term handling of it is more a matter of traffic management, rather than road design. According to our research, traffic operations of road networks with recurrent congestion remarkably differ from the traffic of both the non-congested road networks and the supposed mode of operation of the network, during the planning process. Our results are based on wide-range traffic data collection (traffic counts and trip time measurement) and their analysis. The formation of congestion on a road network with recurrent congestion plays out a typical scenario. In this scenario, some special traffic phenomena play important roles, for example, the wide-range use of alternative routes. The importance of the problem can be seen, as in some cases, within the most important cross-section, as the flow from local roads can reach 70-80% and drivers using alternative routes can reach 30-40% of the total flow. This research outlines a concept which integrates the interesting and important traffic phenomena of recurrent congestion into one theoretical system. The concept provides practical applicability in traffic management and offers the possibility of involving other sciences, such as psychology, sociology and game theory into congestion management. This new concept could fundamentally change the way we think about traffic congestion.

No abstract

Zsolt BarnaCivil engineer, Hungary e-mail: barnazsolt77@gmail.com IntroductionIn case of clothoide transition curves the change of lateral acceleration is even, the values of the third order motion parameters are low. However at the ends of the transition curves the function is discontinuous which in case of high speeds may result unfavorable stresses according to the practical experiences. At other transition curve geometries (cosines, etc) the change of the third order parameters is continuous, but it results significantly higher values for them.As the speed of railway vehicle increased the geometry of transition curves became more nad more important. New methods are developed to analyze the optimal geometry for connecting the sections of different curvature [1][2][3]. This paper describes the bases of a new, efficient transition curve geometry based on hyperbolic functions. At this hyperbolic transition curve the third order h vector -which is particularly important at the geometry design of high-speed railway tracks [4] -is continuous and its value is very close to those values of the clothoide transition curve. The exact characteristics of the hyperbolic transition curve depends on a p parameter.

Numberless Heading] Abstract [Normal] Manuscript preparation for CETRA 2014 proceedings is a fairly simplified process. Everything you need for a properly formatted article is contained in this template document which uses a feature of Microsoft Word called Styles. A style is a set of formatting characteristics that you can apply to text in your document to quickly change its appearance. When you apply a style, you apply a whole group of formats in one simple step. For example, you may want to format the sections headers to make them stand out. Instead of changing the headings one by one, you can give them a style and change them all at once. All the styles in this document are preformatted so you only need to pick an appropriate one for the part you are working on. In this example document each section that uses a specific style starts with a style name surrounded by square brackets for easy identification. The text you are reading at the moment is formatted using [Normal] style, whilst the heading above it uses [Numberless Heading] style and so on. These words serve only as a reference and should be omitted in the paper you submit. Figure 1. Styles dialogue in Microsoft Word 97-2003[Normal] Depending on the version of Microsoft Word you are using, you can access styles in one of two ways. Word 97-2003 features styles as a part of standard formatting toolbar, just left to where you usually choose the font you wish to use. This case is shown in Figure 1. Word 2007-2013 users will find 'Styles' group on the Office ribbon under the 'Home' tab, as shown in Figure 2. This group may be expanded to a list by clicking on the icon in its lower-right corner which will open a window similar to the one in Figure 3.

There are a lot of high expectations about the appearance and spread of autonomous vehicles. There are clear advantages, which can be almost assured: autonomous vehicles will be more comfortable, the number of road accidents will be decreased, more people will gain access to the passenger car's benefits, and unimaginable traffic and business services will be created. Just because of these benefits, it is worth investing considerable resources in the development of autonomous vehicles. There are other expected positive impacts, such as wide-range vehicle sharing and congestion alleviation. However, these latter impacts are not self-explanatory, and research should be taken to ensure that the widespread use of autonomous vehicles results more sustainable urban transport. In this paper, we analyse the impact of autonomous vehicles on congestion. Firstly, we introduce the traffic operation of the road network with recurrent congestion. Secondly, we show that shared use of vehicles reduces congestion only if the sharing of family-owned vehicles is dominant. Otherwise, the users are likely to be mainly former public transport users, cyclists, and pedestrians. Thirdly, we demonstrate that the widespread use of autonomous vehicles reduces congestion only when the new technology improves the capacity of the key cross-section of the network. The capacity of these key cross-sections can only be slightly improved without major construction work, so congestion can only be reduced if there are significantly less vehicles on the road network or the efficiency of traffic flow through autonomous vehicles increases. However, the latter, according to our calculation, is not so favourable to bring about a fundamental improvement in the traffic because of the expected increase in the motorization. Finally, we present some proposals that can contribute to the reduction of congestion on the urban road networks dominated by autonomous vehicles.