Traffic research | PhD research

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Introduction Jump to top of page

From September 2001 up and until June 2006, I worked as a PhD student at the Department of Electrical Engineering ESAT, at the Katholieke Universiteit Leuven, in the research division Systems, Models, and Control (SCD/SISTA/SMC, now grouped under STADIUS), headed by my promotor Bart De Moor (see also the Mathematics Genealogy Project).

My research dealt with transportation planning models and modelling traffic flows on motorways. I was furthermore concerned with the use of cellular automata to model traffic flows, and to simulate large-scale systems efficiently using distributed computing (within the context of integrated dynamic traffic assignment). I was also involved in the handling of large data sets, in particular traffic data stemming from single loop detectors.

In June 2006, this resulted in my PhD dissertation:

Modelling Traffic on Motorways:
State-of-the-Art, Numerical Data Analysis, and Dynamic Traffic Assignment

More information about my dissertation and the thesis defence can be found here; a list of my publications and presentations can be found here.

My PhD committee consisted of the following eight people:

De Moor
De Schutter
Van Houtte

PhD dissertation Jump to top of page

Modelling Traffic on Motorways:
State-of-the-Art, Numerical Data Analysis, and Dynamic Traffic Assignment

Download dissertation text (PDF, 62.83 MiB)


With the levels of congestion in cities and countries showing an ever-increasing trend, the modelling of road traffic continues to be a highly active field. Whereas numerous efforts have been undertaken towards the local and global control of traffic flows, our research is aimed at the modelling part of road traffic, more specifically traffic on motorways.

The goal of this dissertation is three-fold; for starters, we provide a complete nomenclature convention within traffic flow theory, built upon a consistent set of notations. In continuation, we give an in-depth literature survey on the mathematical models used for describing road traffic flows, both from a transportation planning and a flow propagation point of view. Special attention is given to the class of cellular automata models of road traffic. Secondly, we perform an exploratory data analysis of raw traffic flow measurements, discussing the operational characteristics of single-loop detectors. This analysis also provides researchers with tools to track statistical outliers, to quickly assess structural and incidental detector failures, to estimate travel times in an off-line fashion based on raw cumulative counts, and to obtain a visual representation of traffic flow dynamics in time and space. Finally, we provide, within the context of simulation-based dynamic traffic assignment, a straightforward method to tackle both departure time choice and dynamic route choice problems in a sequential manner, built around a traffic flow model that is represented as a computationally efficient cellular automaton.

Our contributions to the field of literature are distinct, in that such comprehensive overviews hitherto only existed in scattered form, whereas we provide a synthesis of the approaches concerning the description of road traffic flows. Furthermore, in contrast to most research on the numerical analysis of traffic flow measurements, we offer methods that are capable of dealing with large-scale data sets in order to get a global picture regarding the quality of the measurements. Finally, as opposed to many approaches towards the paradigm of simulation-based dynamic traffic assignment, we propose a methodology that sequentially integrates departure time choice with route choice within a simulation framework.

Table of Contents:
  • Foreword / Abstract / Korte samenvatting / Table of contents
  • Chapter 1 - Introduction
  • Part I - The Physics of Road Traffic and Transportation
    • Chapter 2 - Traffic flow theory
    • Chapter 3 - Transportation planning and traffic models
  • Part II - Cellular Automata Models of Road Traffic
    • Chapter 4 - Traffic cellular automata
    • Chapter 5 - Relating the dynamics of the STCA to the LWR model
  • Part III - Numerical Analysis of Traffic Data
    • Chapter 6 - Data quality, travel time estimation, and reliability
  • Part IV - Integrated Dynamic Traffic Assignment
    • Chapter 7 - Dynamic traffic assignment based on cellular automata
  • Part V - Conclusions and Perspectives
    • Chapter 8 - General conclusions and future research
  • Appendices
    • Appendix A - Glossary of terms
    • Appendix B - TCA+ Java software
    • Appendix C - Some thoughts on obtaining a PhD
    • Appendix D - Nederlandse samenvatting
  • References / List of publications / List of presentations / About the author

Invitation to the defence Jump to top of page

There is also a PDF version of the invitation available.

Presentation slides Jump to top of page

Here you can find the slides of my presentation (created using LaTeX's Beamer package).
Note that for the animations, an XviD-compatible codec is required.

  • Presentation (PDF, 9.41 MiB)
  • Animation #1; Urban Sprawl (AVI, 97 KiB)
  • Animation #2; Game of Life (AVI, 4.73 MiB)
  • Animation #3; TCA Road Animation (AVI, 2.93 MiB)

Laudatio and photos Jump to top of page

After my presentation and the Q&A with the jury, there was the proclamation given by the head of the jury, followed by a speech in my honour (i.e., the laudatio) given by my promotor. After that, I spoke some words before sending everyone off to the reception.

Dutch audio sample (MP3, 8 min 39 sec, 7.93 MiB)

The photos of the presentation, defence, proclamation, laudatio, and the reception can be found here, in the Photo galleries-section of this website.