A methodology for the simulation based assessment of coordination strategies for signalized networks using Particle Swarm Optimization

The coordination of signal programs at adjacent intersections offers many advantages, the most important being that travel times and emissions can be reduced. However, coordination is a multivariate optimization problem with many constraints. Numerous optimization strategies have been devised in the past. The quality of these coordination strategies depends on three major factors: the quality of the optimization procedure itself, the performance measures it is based upon, and the quality of the input data. In real world applications, the impact of the latter factor in relation to the other factors is commonly a source of great uncertainty. To be able to analyze all three factors, a methodology has been developed to compare different offline optimization strategies using complete information of the traffic flow. The complete information is obtained by using a mesoscopic traffic flow simulation (AVENUE). To have a benchmark for a given optimization function, the best possible coordination for given conditions (traffic demand etc.) is computed using Particle Swarm Optimization (PSO). Different strategies can then be compared to this benchmark and with each other. Furthermore, the stability of the strategies under changing traffic demand and the effect on different performance indices (e.g. number of stops, average delay) can be evaluated. This article describes the methodology, expands upon Particle Swarm Optimiza-tion as a useful tool in signal control, and highlights the opportunities arising out of the chosen approach

User needs for a standardized CO2 emission assessment methodology for Intelligent Transport Systems

The Amitran FP7 project will define a reference methodology to assess the impact of intelligent transport systems on CO2 emissions. The methodology is intended to be used as a reference by future projects and covers both passenger and freight transport. The project will lead to a validated methodology, described in a handbook and complemented by an online checklist. The current paper focuses on the user needs assessment. To ensure the usefulness of the future methodology for potential users, the user needs are identified with the use of interviews, a survey and a workshop. This analysis unveils the demand for a standardised procedure for the assessment of impacts on traveler behaviour and CO2 emissions related to the deployment of ICT in transport. Stakeholders from all fields related to ITS development, deployment, and use from all over Europe are included in the analysis

Influence of Intergreen Times on the Capacity of Signalised Intersections

The quality of road traffic in urban networks is determined by the bottlenecks of the network, which are intersections in most cases. Traffic signals can provide high safety and sufficient capacity at intersections. The capacity of signalised intersections is not only determined by the geometry, layout, and stage settings, it is also influenced by the signal change intervals, when one stage ends and another begins. The interval between the ending of green of one stage or signal group and the beginning or green of another is called intergreen time. During this interval capacity reductions occur. Intergreen times are, though, needed to improve the safety. The presented research analyses the influence of intergreen times on the capacity. Another aim of the research is the promotion of an international dispute on this so far more nationally regarded topic. A thorough literature review, theoretical considerations, and empirical studies at signalised intersections in Germany highlight the improvement potential of the capacity of signalised intersections. Based on the findings, safety related research can be guided towards areas worth consideration from both a safety and capacity point of view. Such areas are, for instance, the entering behaviour of vehicles under saturated conditions, a more distinct consideration of crossing times, and the detailed appraisal of movement sequences (leading to conflicts) with their relevance for the traffic demand and their impact on the capacity. The research not only provides a detailed description of the traffic flow during signal change intervals, but also provides a model for the assessment of intergreen times with reference to the capacity. An application of this model to an example intersection gives a quantitative estimate of the improvement potential of intergreen times: the effective capacity of this signalised intersection is 7% greater than the capacity according to the German Highway Capacity Manual (HBS 2001); the capacity – without further evaluation of the safety impacts – could be improved at maximum by more than 1000 vehicles per hour. Further research into intergreen times is consequently highly recommendable

Estimating service related traffic demand from trip chain data

Commercial traffic constitutes a significant part of total traffic. While on long distances goods traffic prevails, particularly in metropolitan areas service related traffic (i.e. traffic resulting from services delivered to customers at home, offices, constructions sites etc.) takes the lead – and is continuously growing. It is common practice to forecast transport demand for passenger traffic and goods traffic. Dedicated models for service related traffic are still rare. This is not only due to the recognition of the particularities of this special part of traffic among transport planners, it is also due to the complexity of analyzing and depicting service related traffic. One characteristic of service related traffic is that it consists of tours connecting sometimes more than one destination with the origin of the tour. Furthermore, many trips are trips with commercial vehicles, registered by a company or organization, but also private vehicle owners use their cars to some extent for commercial trips. This poses the opportunity to use trip chain data available for private and commercial vehicles to derive total transport demand of service related trips from a sample population. This article introduces such a methodology to extrapolate traffic demand from trip chain data. It is not only applicable to service related traffic, but to all tour based traffic, if empirical tour patterns are available. A regular survey of the German Federal Motor Transport Authority together with detailed spatial and demographic data was used as input to the model. The city of Berlin served as a case study

Implications of Cooperative Adaptive Cruise Control�for the Traffic Flow

Over the past decades goods transportation has been increasing and current widely accepted forecast studies predict a continuation of this trend and a further growth for the coming decades. In order to cope with this growing demand a better use of existing infrastructure is needed. In order to achieve this optimisation of infrastructure use, intelligent transportation systems and telematics are considered of central importance, by political organisations as well as by freight forwarders and drivers. » Scope of the presentation Current research activity is focusing on the driving assistance system Cooperative Adaptive Cruise Control (CACC) by projects like KONVOI, SARTRE and PATH. The CACC-system enables the coupling of several vehicles to build a platoon. Whereas the first vehicle of such a platoon is driven manually, the following vehicles operate fully automated, controlled by the CACC. The technology is developed for long haulage trucks and has been tested successfully already by the RWTH Aachen, Germany. on the road, ,. Furthermore, first simulations of trucks and cars equipped with CACC showed positive effects in form of a harmonisation of the general traffic flow and a reduction of travelling time for the individual vehicle. So far though, it is not known which effects CACC has on the traffic flow on the road in general and the travelling time of platoons of long haulage trucks in a fleet has not been analysed yet. A PhD-thesis, which will be finished this year, is contributing to closing this gap by simulating the scenario. The results of this research project will be presented at the conference. » Objectives of the presentation Practitioners in administration and logistics are addressed by presenting the results of the investigation of impact of cooperative adaptive cruise control on traffic flow. Several implications of the utility of CACC will be demonstrated

Aufwandsoptimiertes Verfahren zur Problemerfassung im Stadtverkehr am Beispiel der Stadt Darmstadt

Wesentliche Voraussetzung für zielgerichtete und effiziente Verkehrsplanung ist die Kenntnis von bestehenden Problemen. Gerade im Stadtverkehr befassen sich eine Vielzahl verschiedener Stellen mit der Erfassung dieser Probleme, angefangen bei Ämtern der Stadtverwaltung und anderen Behörden über Verkehrsunternehmen bis hin zu Interessenvertretungen und Medien. Bislang fehlt jedoch ein geeignetes Verfahren, um die vielfältigen vorhandenen Informationen für eine integrierte Verkehrsplanung nutzbar zu machen. Diese Arbeit setzt sich deshalb systematisch mit den Grundlagen und Randbedingungen der Problemerfassung auseinander, um daraus ein aufwandsoptimiertes Verfahren zur Problemerfassung im Stadtverkehr zu entwickeln. Kern des Verfahrens bildet ein Problemkataster, in dem die Informationen über Probleme in geeigneter Form gespeichert werden können und dadurch einen Überblick über die aktuelle Situation des Verkehrssystems ermöglichen. Der Schwerpunkt liegt auf dem methodischen Vorgehen, welches auf die Verkehrsqualität ausgerichtet ist. Im Mittelpunkt stehen off-line Daten. Der Detaillierungsgrad der Umsetzung bleibt stellenweise auf einem recht niedrigen Niveau, welches für das Verständnis ausreicht und die Übersichtlichkeit erhöht. Die im jeweiligen Anwendungsfall erforderlichen Anpassungen werden erläutert. Zu Beginn der Arbeit werden die Ziele des Verfahrens dargelegt und die Grundlagen, auf denen es aufbaut, beschrieben. Zu diesen Grundlagen gehören die Ziele der Verkehrsplanung und die Beschreibung und Kategorisierung von Problemen. Mögliche Erfassungsmethoden werden kurz erläutert. Auf wichtige Aspekte im Zusammenhang mit Datenverbünden wie Kooperation, Organisation, technische Belange und Standards wird eingegangen. In der Arbeit wird eine Methodik entwickelt, die vorhandene Problemerfassung auf Vollständigkeit und Qualität zu überprüfen. Es wird dabei zunächst ein angestrebter Soll-- Zustand definiert, der mit der tatsächlichen Situation verglichen werden kann. Für die systematische Erfassung des Ist--Zustandes dienen ein Quellenkatalog, in dem alle an der Problemerfassung potentiell beteiligten Stellen aufgelistet werden, sowie ein Interviewleitfaden für die zielgerichtete Befragung dieser Stellen. Als Teil der Analyse der Problemerfassung werden Kriterien wie Plausibilität, Aktualität und Aussageschärfe von verfügbaren Informationen behandelt. Es wird darüber hinaus der Aufwand zur Nutzbarmachung dieser Informationen untersucht, und Wege aufgezeigt, ihn zu verringern. Informationen über Probleme werden in die drei wesentlichen Bestandteile Problemart, Ort des Auftretens und Zeit des Auftretens zerlegt. Diese drei Bestandteile werden weiter untergliedert und einer Kategorisierung zugeführt. Diese Kategorisierung dient einer hohen Funktionalität des Problemkatasters. Vielfältige Abfragen werden dadurch möglich. Voraussetzung für die eindeutige Zuordnung von Problemen und eine Anbindung der Datenbank an Geographische Informationssysteme (GIS) zur anschaulichen grafischen Visualisierung ist eine Georeferenzierung der Probleme. Das Verfahren bietet die Möglichkeit, in der Praxis verwendete einfache Beschreibungen (Straßennamen, Hausnummern, Haltestellen etc.) mit georeferenzierten Datenbanken zu verknüpfen. Das Datenmodell des Problemkatasters weist über die Beschreibung eines Problems hinaus den einzelnen Einträgen (Instanzen) Bearbeitungsattribute wie Prüf- und Bearbeitungsstatus, Aktualisierungsdatum, Bearbeiter und erfassende Stelle zu. Ergänzt durch eine Übersicht über vorhandenes Datenmaterial zu einem Eintrag und die Erfassungsmethode des jeweiligen Problems kann das Problemkataster als Register bei der Problembearbeitung verwendet werden (Verknüpfungspunkt). Die verschiedenen Möglichkeiten der organisatorischen Umsetzung eines Problemkatasters werden in die Bereiche Dateneingabe (Input), Pflege des Katasters und Datenzugriff (Output) unterteilt. Es wird zwischen zentraler und dezentraler Organisation unterschieden. Als Bewertungsmethode dient eine Nutzwertanalyse. >Die technische Umsetzung hängt maßgeblich von den gegebenen Randbedingungen ab, weshalb nur die zu beachtenden Punkte erläutert werden. Die konkrete Realisierung in Bezug auf Hardware und Software ist nicht Bestandteil dieser Arbeit. Um den Nutzen des Verfahrens weiter zu erhöhen, kommen eine Vielzahl von Möglichkeiten in Betracht. Nicht nur das Problemkataster an sich kann für eine Effizienzsteigerung der Problemerfassung, Aufzeigen von Zusammenhängen, Prioritätensetzung bei der Maßnahmenbewertung u.ä. verwendet werden, auch der Quellenkatalog, während der Umsetzung des Verfahrens kontinuierlich mit zusätzlichen Informationen wie Ansprechpartnern und Hintergrundinformationen gefüllt, oder die organisatorische und technische Infrastruktur des Verfahrens können über die Kernziele hinaus genutzt werden. Die Anwendung des entwickelten Verfahrens zur Bewertung der Problemerfassung und Nutzbarmachung der gesammelten Informationen wird beispielhaft an der Stadt Darmstadt gezeigt. Dabei wird die Situation in Darmstadt zunächst analysiert. Mittel hierzu sind Gespräche anhand des Interviewleitfadens mit den für ein Problemkataster wichtigsten Stellen. Die hierbei gesammelten Informationen geben Aufschluss über vorhandene Problemerfassung und organisatorische wie technische Umsetzungsmöglichkeiten eines Problemkatasters. Es werden Lücken in der Problemerfassung aufgezeigt und Möglichkeiten geschildert, diese Lücken zu schließen und die Qualität der Problemerfassung weiter zu verbessern. Schließlich werden Probleme der Verkehrsqualität in Darmstadt im Datenmodell des Problemkatasters abgebildet und auf verschiedene Arten dargestellt. Den Abschluss der Arbeit bietet ein Ausblick auf Möglichkeiten, das Verfahren auszuweiten und dadurch die Funktionalität und Nutzbarkeit des Problemkatasters weiter zu erhöhen. Das Verfahren und insbesondere seine Umsetzung im Rahmen dieser Arbeit werden auch kritisch hinterfragt und Mängel aufgezeigt. Bestandteil der Arbeit ist ein kurzer Leitfaden, der die wichtigsten Schritte bei der Entwicklung und Umsetzung eines Problemkatasters zusammenfasst und mit Verweisen auf den Text versehen ist. Anhand der Situation in Darmstadt lässt sich erkennen, dass einerseits die Integration der Verkehrsplanungsprozesse recht weit fortgeschritten ist und der zusätzliche Nutzen durch ein Problemkataster eingeschränkt ist, andererseits viele kleine Verbesserungsmöglichkeiten zu erkennen sind, die das Verfahren ausfüllen kann. Genau darauf ist das Verfahren ausgerichtet, da es durch seine einfache Grundstruktur mit geringem Aufwand verwirklicht werden kann, um im Laufe der Zeit erweitert zu werden. Gerade die Datenbank an sich wird ihre Wirkung erst mit zunehmendem Umfang und Bekanntheitsgrad entfalten. Wichtig ist deshalb die begleitende Öffentlichkeitsarbeit (zumindest bei den an der Verkehrsplanung beteiligten Stellen) und gute Kooperation. Die Einbindung des Problemkatasters in Verkehrsmanagementsysteme oder umfangreichere Verkehrsinformations-Datenbanken ist möglich und sinnvoll, eine Erweiterung denkbar

Effects of Traveller Information Systems on the Behaviour of the Users

Traveller information systems (TIS) play an increasingly important role in the improvement of transport systems, and, hence, are an important part of them. This importance can be seen in an influence of travellers through information systems. The attractiveness of a transport mode depends apparently among other factors on the traveller information on this mode. The importance of traveller information in understanding travel behaviour has been recognised already. Particularly the ways through which the information exerts its influence and the quantitative and qualitative impacts of it has, however, not yet been researched comprehensively. One reason can be found in the complexity of the topic, another in the high costs for a sound data collection. The British Department for Transport develops a multimodal traveller information system for Great Britain under the name of "Transport Direct". As a preparation research has been initiated and financed. This thesis deals with parts of the research topics identified as being important for the development of Transport Direct. The focus is drawn on multimodal traveller information particularly for public transport and the role of information on the end-- leg of trips concerning the mode choice for the main leg. The first three sections describe the findings of a literature review on traveller information systems and travel behaviour. To introduce into the broad topic of traveller information systems and their impacts, in the first of them the different kinds of existing systems, possible user groups, probable future development, and aims of the systems are described. The second section deals with travel behaviour in general and the possible ways of influencing it. The important factors are described and models to explain decision making processes are presented. The development in the recent years from simple linear models using explanatory variables towards more complex socio--psychological theories is shown. With the important terms and the basics of traveller information systems explained and user behaviour described, the available evidence in the literature for influences of multimodal traveller information on the user behaviour is analysed in the third section. It can be seen that most research lacks sufficient longitudinal data and deals either with specific projects or unspecific fundamentals. Many results indicate a potential for traveller information to influence the users, but few quantitative and detailed data can be found. The main role seem to play changed attitudes. Most of the research is funded by governments and the European Union. The attention of this research is drawn particularly on mobility centres, which try to fill the gaps resulting from transport operator oriented information. One important problem occurring is the difference between expected information (user) and presented information (to provide integrated multimodal information). Other potential problems are inundation with information and personalised information. The role of traveller information systems and its effects in the context of other measures (e.g. campaigns, regional integration, politics) is described. Moreover, it can be seen that traveller information systems have also undesired impacts (e.g. social exclusion, reducing natural variation, enhancing existing attitudes). With the background of this literature review a research area is chosen which still offers substantial possibilities for further analysis, while it is important for the understanding of traveller information and its effects on the user behaviour (especially in the context of Transport Direct): the field of information on the end--legs of multi leg trips. In this thesis the focus is drawn particularly on walking as the transport mode for the end--leg. As the basis for a survey four hypotheses are phrased, which try to catch in four steps as only a small part of possible effects the influence of end--legs on the transport mode for the main leg, the role of information for the main leg, a correlation of walking and the usage of public transport, and the influence of information in increasing the attractiveness of walking. Through more detailed objectives aiming in the first place at proving or refuting the hypotheses a survey is developed. The way of developing the survey including survey sample, sample frame, survey instrument, questionnaire, and used material is described. The survey was planned and realised as a streetside interview in the city centre of Southampton (Hampshire). Changes made after piloting the survey due to problems like length of interviews, misleading questions and unsuitable material (e.g. maps) are explained. The results of the survey cannot dependably proof the hypotheses, but give several indications of important aspects concerning traveller information at its effects. Simple maps appear to be most useful for travellers as opposed to written descriptions or comprehensive maps with a high degree of detail and additional information. The results of questions on probable behavioural changes show the importance of information in decision making on transport modes. The role of user groups is shown for basic categories like `frequent public transport user', `old traveller', or `(fe)male traveller'. It appears that some attitudes and perceptions are correlated considerably to user groups (e.g. perceiving the distance of end--legs, seeking information, perception of stages of public transport trips, importance of coloured maps), while others seem to be quite homogenous concerning user groups (e.g. considering the distance of end-- legs, impediments to walking). However, the realisation of the survey revealed not only important research areas for detailed future examinations, but showed also some problems of conducting surveys like this. Therefore a number of potential improvements are presented. A suitable survey instrument and sample size in achieving more representative and reliable results is important. Some questions could be extended upon and more objectives should be included in a bigger survey

Transport cost: An aggregated model for surface freight transport based on cost components and market segments

Transport cost is one of the most decisive influencing factors for transport and logistics operations. Policy makers face the challenge that measures they implement to make transport more sustainable change transport costs, sometimes in a complex manner that requires detailed knowledge of cost structures. For single shipments the costs can be calculated in detail. However, on an aggregated level spanning numerous shipments or even the whole transport system this is rarely possible. Yet policy assessment relies on accurate cost estimates. It is therefore important to understand the relevance of simplifications and to consider for all effects the implementation of measures has on transport costs. In this contribution we analyse the structure of transport costs for railway, road, and inland waterway freight transport. A model is introduced that calculates distance dependent freight rates. It accounts for different market segments and differences between modes and is based on estimates of detailed cost components. The model is applied to different policy measures addressing modal shift to demonstrate their effect on transport costs. Transport costs are divided into components like personnel costs, vehicle costs, maintenance costs, energy costs, and handling fees. Different market segments (e.g. combined transport, bulk goods, general cargo) are distinguished. The model uses average costs of the various components (from vehicle costs to energy prices) based on data of the German transport market. Average utilisation and load factors of the relevant vehicle/train types are an important input to overall cost comparisons. The contribution will, hence, look at the sensitivity of the cost calculation to these often uncertain inputs, particularly those which require an in depth knowledge of the underlying transport system or of the decision framework of selected actors which is often not available and replaced by assumptions. The model results are validated against freight rates available in the literature. The systematic approach of the contribution facilitates transfer to different contexts and adaptation to different needs. The model is applied in freight transport modelling for policy assessments in Germany

Multimodal Assessment of Signalized Intersections Considering the Number of Travellers

The purpose of transportation networks is the efficient and sustainable movement of people and goods. However, established evaluation procedures commonly assess the traffic quality instead of the transport quality, i.e. they focus on vehicles instead of goods and travellers. Furthermore, the existing methodologies evaluate the quality of each transport mode separately and often neglect the role of bicycles and pedestrians. Recently, several methods have been proposed to consider transport networks from a multimodal perspective, which is an important step towards the transport quality evaluation in the context of sustainability. A transparent and objective evaluation methodology is needed which comprehensively considers all transport modes. The procedure introduced in this article is limited to the assessment of signalized intersections, but goes one step beyond the existing methods: the multimodal assessment considers the number of travellers of the different modes. A route importance factor is introduced to reflect the differing significance of the transport modes. A case study underlines the strengths of the procedure

Der Einfluss der Zwischenzeiten auf die Kapazität von Knotenpunkten mit Lichtsignalanlage

In dem Beitrag wird der Frage nachgegangen, wie groß an Knotenpunkten mit Lichtsignalanlage der Einfluss von Zwischenzeiten auf die Kapazität ist. Der Verkerhsablauf während des Phasenwechsels wird detailliert erläutert. Ein Ansatz zur Ermittlung der effektiven Freigabezeiten und der effektiven Kapazität wird vorgestellt. Anhand von Messungen für die einzelnen Verkehrsvorgänge im Phasenwechsel bei gesättigtem Verkehrsfluss wird bestätigt, dass entgegen dem in Deutschland üblichen Ansatz zur Kapazitätsermittlung ein nennenswerter Teil der Zwischenzeit zur Kapazität beiträgt. Dementsprechend wird vorgeschlagen, zukünftig eine effektive Freigabezeit bei der Kapazitätsermittlung zu verwenden. Darüber hinaus werden die Potenziale einer situationsabhängigen und dynamischen Bemessung von Zwischenzeiten aufgezeigt. Weiter Forschungen zur Berücksichtigung des stochastischen Charakters der Verkehrsvorgänge im Phasenwechsel und zur Vertiefung von Sicherheitsaspekten werden angeregt. Der Beitrag basiert auf einem von der Deutschen Foschungsgemeinschaft geförderten Projekt, welches am Fachgebiet Verkehrsplanung und Verkehrstechnik der TU Darmstadt bearbeitet wurde. The article addresses the question, to which extent the intergreen times at signalised intersections affect the capacity. The traffic flow during the signal change is explained in detail. An approach to calculate the effective green time and effective capacity is presented. By various field surveys carried out under saturated traffic conditions, it was confirmed that an essential part of the intergreen times contributes to the effective capacity of intersections. Based on the case of Germany, it is recommended to use effective green times for the capacity calculations. Moreover, the potentials of a situation dependent and of a dynamic determination of intergreen times are highlighted. Further research on the stoachstic characteristic of traffic flow during signal change and its impact on safety is recommended