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Über dieses Buch

Anyone who reflects on the future of society cannot do so without at the same time thinking about the future of our transportation systems. The dilemma is obvious. On the one hand, mobility must be maintained as it is crucial to economic development and because people are eager for individual mobility. On the other hand, traffic imposes heavy burdens on people and on the environment, on cities and communities and on our national economies. Finding a solution to that dilemma seems to be difficult, in fact we have not even developed a rough idea of how it could look like. This is why the North Rhine-Westphalia Science and Research Ministry came up with the plan to work out a well-founded scientific basis on which to solve the problems inherent in our transport system. A research network has been established and sponsored with government funds for a period of three years with a view to realising that objective. The "Traffic Simulation and Environmental Impact" research network is composed of researchers who have an excellent reputation as North Rhine-Westphalia traffic experts. Cutting across various disciplines of knowledge, the network aims to integrate transportation and natural sciences, particularly physics and mathematics, in a move to profit by the synergy between technical know-how and innovative methodology. The present volume is intended as a progress report and a prologue to the forthcoming international colloquium which represents the highlight and at the same time the end of the three-year project funding period.



Economic Factors of Traffic Generation


Multicriteria Demand Reaction Analysis in Passenger Transport

Current findings of transport policy about its impacts and the reactions of transport demand on pricing or regulatory measures are unsatisfactory. One criticism of previous demand reaction analyses comprises the relatively uniform modeling. However, transport participants react on changes of traffic conditions quite differently. This study aims at going beyond these uniform approaches and at working out the variety of transport demand reactions.
H. Baum, K. Esser

Traffic Generation


Dynamic Estimation of Transport Demand: Solutions — Requirements — Problems

The following contribution presents requirements, difficulties and first attempts at modelling a temporal short interval estimation of transport demand. For the simulation of motorway traffic (for an area within the state of North-Rhine-Westfalia, NRW) methods of temporal disaggregation of existing trip-matrices have been worked out within the framework of the Northrhine-Westfalian research cooperation for traffic simulation and environmental impacts “NRW-FVU” (Nordrhein-Westfälischer Forschungsverbund Verkehrssimulation and Umweltwirkungen). To simulate urban traffic (example: Wuppertal) methods of estimating temporal short interval trip-matrices were conceived and tested. The matrices were supplied for microsimulation with Cellular Automat (CA) and for the dynamic route choice and traffic assignmemt (DRUM, Dynamische Routensuche and Umlegung). The comparison of both methods, based on the estimated link loads (ADT and hourly loads), supplies deviations ranging within the mean variation of counted values. It therefore can be inferred that these methods, which are different with regard to computing intensity and data requirements, should be used depending on the tasks and the intended precision of the results. The specific pros and cons are important operational criteria. It also becomes obvious that in future methodical advancements should be examined on the basis of activity(-chain)-based approaches.
K. J. Beckmann, G. Rindsfüser

The Development of a Unified Modeling Framework for the Household Activity-Travel Scheduling Process

The goal of this paper is to propose a new approach to activity-travel schedule modeling that provides a unifying framework for past research in different areas. This approach is based on empirical evidence gathered using a Computerized Household Activity SchEduling (CHASE) survey. The survey provided a means to examine the underlying scheduling behavior of household over a one week period as it occurs in reality. Results show that a clear distinction can be made between routine scheduling decisions that are pre-planned before the week commences, and the more short-term, impulsive, opportunistic decisions made as the schedule is executed during the week. This distinction allows one to conceptualize the modeling task as a multi-stage process, wherein routine planning is approached with existing optimization models (assuming that routine activities are the result of a long-term thought and experimentation process) followed by a more sub-optimal rule-based simulation model to replicate the decisions process during the week within the constructs of the optimal routine plan. Such a model is proposed in this paper as a long term development, and would rely on the type of data provided by new data collection techniques such as CHASE. Operationalization of the model as an event-oriented simulation is proposed. Various components of the model are explored in detail, and discussed within context of existing models.
S. T. Doherty, K. W. Axhausen

The Development of ALBATROSS: Some Key Issues

This paper discusses some experiences with the development of ALBATROSS, a rule-based system for predicting transport demand, currently under development for the Dutch Ministry of Transport, Public Works and Water Management. The model belongs to the class of activity-based models, implying that it attempts to predict which activities are conducted where, when, with whom, for how long, and the transport mode involved. In principle, this increased complexity allows one to predict the impact of urban and transport policies and institutional change on activity patterns and hence transport demand, but this increased complexity also involves new theoretical, and methodological challenges and problems of data collection. Some of these challenges are briefly discussed in this paper. In particular, the conceptualisation of activity behaviour, the derivation of choice heuristics from diary data, the development of appropriate goodness-of-fit measures and the problem of data quality are discussed.
T. A. Arentze, F. Hofman, C. H. Joh, H. J. P. Timmermans

Analysis of Traffic Flow of Goods on Motorways by Means of Video Data — Chances and Limits

In a field study in the area of Aachen-Düsseldorf-Köln a procedure of documentation and analysis of goods traffic streams on motorways with videodata was applied. After an extensive preparation all data had been transferred into origin destination matrices. Due to this reliable statements on the traffic situation during the observation period could be made. In this way, the basic applicability of the procedure was shown
K. Henning, K. Grobel, H. Saß

Estimating Path Flows from Traffic Counts

The theory and use of the Path Flow Estimator (PFE) as a one-stage network observer in support of urban traffic management and control is presented. Following an outline of the theory, initial results from the CLEOPATRA and COSMOS projects are reported. Underlying the PFE is a flexible capacitated stochastic user equilibrium traffic assignment method which provides unique estimates of path flows and path travel times from traffic count and prior origindestination data. To accommodate transitory overloading, time-dependent delay functions are used whereby final queues in one time slice are passed forward as initial queues for the next. The PFE is programmed in C, and can run on a variety of platforms. Efficient use of memory means that large networks can be handled in real time on a PC, although the algorithm stores and processes individual paths.
M. G. H. Bell, S. Grosso

Traffic Flow Theory, Networks


Remarks on Traffic Flow Modeling and Its Applications

This document presents some recent results and ideas from the University of California (Berkeley) traffic operations group, and at the same time discusses the role of traffic flow modeling in traffic management and control. It stresses the steps that can be taken to reduce congestion and improve traffic efficiency, and how traffic models and theories fit within this picture.
C. F. Daganzo

Online Traffic Simulation with Cellular Automata

The development of dynamic traffic information systems is one of the most important challenges in the field of Intelligent Transportation Systems ITS. A promising way is to couple simulations of the actual traffic state together with online counting data stemming from detection devices, e.g. induction loops. The aim is to generate a one-to-one image of the individual on-road car motion in the computer and to derive the relevant information from the simulation results. In addition, the simulation serves as an “interpolation” for regions which are not adequately covered by measurements. In this contribution the method of online simulations is discussed and some results are reported.
R. Barlovic, J. Esser, K. Froese, W. Knospe, L. Neubert, M. Schreckenberg, J. Wahle

Census-Based Travel Demand Generation for Transportation Simulations

During the last decades, a lot of progress has been made in understanding the dynamics of traffic flow models. Real world applications of these models require the ability to model traffic in networks, which has been an important research topic lately. We focus on the problem of travel demand generation in transportation networks. Our investigations are based on real world data for the Portland/Oregon area. We present a microscopic approach for iterative activity assignment exemplarily for home-to-work trips. It provides a method to generate real-world macroscopic data - in our case it is the travel time distribution resulting from census data - in a network traffic simulation under simulation feedback. The underlying assignment is based on a simple ansatz to split the probability of choosing a workplace in a particular distance into a term which describes the accessibility of workplaces, and the individuals’ function of travel time acceptance. In combination with the census data, this approach provides the macroscopic acceptance function, which turns out to be an exponentially decaying function plus a ‘repulsive’ behavior for small travel times. Furthermore, these investigations demonstrate that iterative activity assignment on a microscopic level is computationally feasible even for realistically sized transportation systems.
J. Esser, K. Nagel

Some New Approaches to the Microscopic Modelling of Traffic Flow and the Dynamic Route Assignment Problem

In order to simulate the transportation system of a large region dynamically, three things have to be known and modelled: who wants to go where at what departure time (destination choice), which route to the destination is selected (route choice), and finally how the locomotion along this route is performed in time (travelling). This article deals with the second and third question. Firstly, it is shown how the dynamic route choice problem could be solved by a simulation—based approach. Surprisingly, when comparing this approach to the classic static one, it turns out to be simpler and applicable to larger networks than its classical counterpart. Secondly, by using a simplified model of car—following, most of the phenomena observed in real traffic can be reproduced by the simulation. The realism achieved with this model allows a reliable estimation of the emissions caused by traffic (car traffic amounts to roughly 80% of the total travel volume). The model is numerically very efficient, enabling the simulation of large road networks with more than 1 million individual cars in real time Finally, preliminary results are mentioned concerning the possibility of expanding this simplified microscopic approach to the destination choice modelling. Following this route of thinking further finally leads to an integrated, microscopic, and dynamic approach to transportation planning and control. The first steps toward this aim has been done within the FVU.
R. Böning, G. Eisenbeiß, C. Gawron, S. Krauß, R. Schrader, P. Wagner

Evaluation of Cellular Automata for Traffic Flow Simulation on Freeway and Urban Streets

A Cellular Automaton is a extremely simplified program for the simulation of complex transportation systems, where the performance velocity is more important than the detailed model accuracy. The first application of the Cellular Automaton for simulation of traffic flows on streets and highways was introduced by Nagel and Schreckenberg [7]. The basic Cellular Automaton model from Nagel-Schreckenberg has been checked against measurements of realistic traffic flow on urban streets and motorways in Germany. It was found that the measured capacities on German motorways cannot be reproduced very well. On urban streets, however, it was very well possible to represent traffic patterns at intersections. The paper describes a completely new concept for the cellular automaton principle to model highway traffic flow. This model uses a time-oriented car-following model. This model accounts for the real driving behavior more precisely than the model from Nagel and Schreckenberg. This paper shows that a Cellular Automaton is generally applicable for simulation of traffic flows. The degree of correspondence with reality depends on the applied car-following model. The new model concept combines realistic modeling with fast computational performance.
W. Brilon, N. Wu

Effects of New Vehicle and Traffic Technologies — Analysis of Traffic Flow, Fuel Consumption and Emissions with PELOPS

This contribution presents the conception and application possibilities of the program system PELOPS that is being applied in the Northrhine-Westphalia Research Cooperative “Traffic Simulation and Impacts on the Environment”, in order to predict the influence of new vehicle- and traffic concepts on the traffic flow and emissions. Apart from the presentation of the vehicle-orientated traffic simulation program PELOPS single focal points of projects of the Institut für Kraftfahrwesen Aachen (ika) in the frame of the FVU are shown and concrete application examples for PELOPS are demonstrated. Particular attention is paid to the calculation of emissions of traffic and to an explanation of necessary actions.
H. Wallentowitz, D. Neunzig, J. Ludmann

Traffic Simulation for the Development of Traffic Management Systems

This paper describes the industrial application of traffic simulation at Robert Bosch GmbH. The role of traffic simulation in the design process of traffic management systems and the way of working of Bosch R&D are presented. The main features of Bosch’s simulation environment ARTIST (Advanced Research Tool for Indoor Simulation of Traffic) are described. Sample applications in the area of freeway management systems and urban traffic light control demonstrate how traffic simulation is currently used in the product development process. ARTIST’s flexibility allows the usage of domain specific traffic models that are best suited to the specific task.
W. Krautter, D. Manstetten, T. Schwab

Modelling Advanced Transport Telematic Applications with Microscopic Simulators: The Case of AIMSUN2

The simulation of Advanced Transport Telematic Applications requires specific modelling features, which have not been usually taken into account in the design of microscopic traffic simulation models. This paper discusses the general requirements of some of these applications, and describes how have they been implemented in the microscopic traffic simulator AIMSUN2.
J. Barceló, J. Casas, J. L. Ferrer, D. García

Environmental Effects


Modelling of Regional and Local Air Pollution Based on Dynamical Simulation of Traffic

In the Wuppertal area, Germany, air pollution due to the emission of vehicles is calculated for two summer smog episodes in 1996 and 1997 using a coupled system of atmospheric models that are applicable to different scales. The model system CARLOS (Chemistry and Atmospheric transport in Regional and Local Scale) contains complex subsystems for simulating the atmospheric transfer and the chemistry of gaseous pollutants. The system is capable of reproducing the basic structures of measured data A higher spatial resolution of the simulations enhances the details of the modelled concentration and wind fields.
W. Brücher, M. J. Kerschgens, C. Kessler, A. Ebel

Interaction of Traffic and Other Anthropogenic Emissions in Polluted Regions and Their Environment

Traffic and air quality as aims of the FVU are interconnected and interdisciplinary. CARLOS is a combination of two comprehensive air quality simulation models to calculate chemistry and transport in regional and local scales. Both models apply nesting techniques to describe the influx into the modeling domain. High resolution emission inventories are available for the innermost nest in the large scale, which allow the separate description of traffic and point sources. Results of a simulation for Nordrhein-Westfalen in August 1997 are presented with two nesting levels, increasing the resolution from 27 km in Central Europe to 3 km in the domain of nest2. Comparison of observations at three TEMES-stations with modeled concentrations show a close agreement of ozone and a reasonable reproduction of NO2. Three zerocases are discussed, where industry and point sources as well as traffic are considered in their contribution to ozone production. All cases show a considerable reduction of maximum ozone levels and reductions in mean levels of nitric oxides.
C. Kessler, W. Brücher, M. Memmesheimer, M. J. Kerschgens, A. Ebel

Time Soluted Assessment of Traffic Impacts in Urban Areas Based on Dynamic Traffic Simulation

The task of LUIS within the research cooperative is the assessment of time soluted traffic impacts in towns. For this, time dependent limit values for a compatible traffic volume had to be developed. They are defined as the maximum number of vehicles per street section for the period 1/2 h. Furthermore, urban space types and their sensitivity had to be determined. By that, in the future it will be possible to integrate aspects of compatibility in the development of control strategies for the motorized individual traffic.
F. Huber, S. Kaufmann


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