th It is our great privilege and honor to present the proceedings of the 18 International Symposium on Transportation and Traffic Theory (ISTTT), held at The Hong Kong Polytechnic University in Hong Kong, China on 16-18 July 2009. th The 18 ISTTT is jointly organized by the Hong Kong Society for Transportation Studies and Department of Civil and Structural Engineering of The Hong Kong Polytechnic University. The ISTTT series is the main gathering for the world’s transportation and traffic theorists, and those who are interested in contributing to or gaining a deep understanding of traffic and transportation phenomena in order to better plan, design and manage the transportation system. Although it embraces a wide range of topics, from traffic flow theories and demand modeling to road safety and logistics and supply chain modeling, the ISTTT is hallmarked by its intellectual innovation, research and development excellence in the treatment of real-world transportation and traffic problems. The ISTTT prides itself in the extremely high quality of its proceedings. Previous ISTTT conferences were held in Warren, Michigan (1959), London (1963), New York (1965), Karlsruhe (1968), Berkeley, California (1971), Sydney (1974), Kyoto (1977), Toronto (1981), Delft (1984), Cambridge, Massachusetts (1987), Yokohama (1990), Berkeley, California (1993), Lyon (1996), Jerusalem (1999), Adelaide (2002), College Park, Maryland (2005), and London (2007). th th This 18 ISTTT celebrates the 50 Anniversary of this premier conference series.

The understanding of empirical traf?c congestion occurring on unsignalized mul- lane highways and freeways is a key for effective traf?c management, control, or- nization, and other applications of transportation engineering. However, the traf?c ?ow theories and models that dominate up to now in transportation research journals and teaching programs of most universities cannot explain either traf?c breakdown or most features of the resulting congested patterns. These theories are also the - sis of most dynamic traf?c assignment models and freeway traf?c control methods, which therefore are not consistent with features of real traf?c. For this reason, the author introduced an alternative traf?c ?ow theory called three-phase traf?c theory, which can predict and explain the empirical spatiot- poral features of traf?c breakdown and the resulting traf?c congestion. A previous book “The Physics of Traf?c” (Springer, Berlin, 2004) presented a discussion of the empirical spatiotemporal features of congested traf?c patterns and of three-phase traf?c theory as well as their engineering applications. Rather than a comprehensive analysis of empirical and theoretical results in the ?eld, the present book includes no more empirical and theoretical results than are necessary for the understanding of vehicular traf?c on unsignalized multi-lane roads. The main objectives of the book are to present an “elementary” traf?c ?ow theory and control methods as well as to show links between three-phase traf?c t- ory and earlier traf?c ?ow theories. The need for such a book follows from many commentsofcolleaguesmadeafterpublicationofthebook“ThePhysicsofTraf?c”.

The transportation problem can be formalized as the problem of finding the optimal way to transport a given measure into another with the same mass. In contrast to the Monge-Kantorovitch problem, recent approaches model the branched structure of such supply networks as minima of an energy functional whose essential feature is to favour wide roads. Such a branched structure is observable in ground transportation networks, in draining and irrigation systems, in electrical power supply systems and in natural counterparts such as blood vessels or the branches of trees. These lectures provide mathematical proof of several existence, structure and regularity properties empirically observed in transportation networks. The link with previous discrete physical models of irrigation and erosion models in geomorphology and with discrete telecommunication and transportation models is discussed. It will be mathematically proven that the majority fit in the simple model sketched in this volume.

“Everything should be made as simple as possible—but not simpler” Albert Einstein Traffic Theory, like all other sciences, aims at understanding and improving a physical phenomenon. The phenomenon addressed by Traffic Theory is, of course, automobile traffic, and the problems associated with it such as traffic congestion. But what causes congestion? Some time in the 1970s, Doxiades coined the term "oikomenopolis" (and "oikistics") to describe the world as man's living space. In Doxiades' terms, persons are associated with a living space around them, which describes the range that they can cover through personal presence. In the days of old, when the movement of people was limited to walking, an individual oikomenopolis did not intersect many others. The automobile changed all that. The term "range of good" was also coined to describe the maximal distance a person can and is willing to go in order to do something useful or buy something. Traffic congestion is caused by the intersection of a multitude of such "ranges of good" of many people exercising their range utilisation at the same time. Urban structures containing desirable structures contribute to this intersection of "ranges of good". xii Preface In a biblical mood, I opened a 1970 paper entitled "Traffic Control -- From Hand Signals to Computers" with the sentence: "In the beginning there was the Ford".

This report addresses the fundamental challenges that climate change poses to infrastructure owners, who face two major challenges. First, they must ensure continued asset performance under sometimes significantly modified climate conditions that may decrease the present value of their networks ...