abstract: Contrary to many previous travel demand forecasts there is increasing evidence that vehicle travel in developed countries may be peaking. The underlying causes of this peaking are still under much debate and there has been a mobilization of research, largely focused at the national scale, to study the explanatory drivers but research focused at the metropolitan scale, where transportation policy and planning are frequently decided, is relatively thin. Additionally, a majority of this research has focused on changes within the activity system without considering the impact transportation infrastructure has on overall travel demand. Using Los Angeles County California, we investigate Peak Car and whether the saturation of automobile infrastructure, in addition to societal and economic factors, may be a suppressing factor. After peaking in 2002, vehicle travel in Los Angeles County in 2010 was estimated at 78 billion and was 20.3 billion shy of projections made in 2002. The extent to which infrastructure saturation may contribute to Peak Car is evaluated by analyzing social and economic factors that may have impacted personal automobile usage over the last decade. This includes changing fuel prices, fuel economy, population growth, increased utilization of alternate transportation modes, changes in driver demographics , travel time and income levels. Summation of all assessed factors reveals there is at least some portion of the 20 billion VMT that is unexplained in all but the worst case scenario. We hypothesize that the unexplained remaining VMT may be explained by infrastructure supply constraints that result in suppression of travel. This finding has impacts on how we see the role of hard infrastructure systems in urban growth and we explore these impacts in the research. / Dissertation/Thesis / M.S. Civil Engineering 2014

Dans le cadre d’une analyse longitudinale centrée sur l’Ile-de-France, nous abordons la question du Peak Car, hypothèse de recherche selon laquelle le plafonnement de l’usage automobile dans de nombreux pays développés pourrait être le signe d’un repli de long terme de la mobilité automobile.En utilisant les données des EGT et du panel Parc Auto depuis les années 1970, on constate que le plafonnement du kilométrage des ménages apparait dès le début des années 1990 suivie d’une baisse continue à partir de 2000, et même actuellement dans un contexte de prix bas des carburants.Face au débat sur le Peak Car, nous montrons que si le prix des carburants a joué un rôle important sur le retournement de tendance, d’autres facteurs multidimensionnels influencent. C’est le cas de la forte baisse de la mobilité des jeunes, qui s’étend aux classes d’âges plus avancés, prémisses d’un changement d’usage à venir. Certains moteurs de la croissance sont aussi en voie d’achèvement et pourraient venir renforcer le Peak Car : rapprochement de la mobilité homme/femme, fin de la hausse de la mobilité des retraités et de la diffusion sociale de la voiture. La décorrélation de l’effet du revenu, synonyme d’une saturation du besoin de mobilité, s’opère aussi sur la motorisation. Le rapprochement du comportement entre groupes de revenu pourrait venir renforcer ce phénomène.Enfin, le rôle des opinions reste incertain. La conscience écologique ne semble pas jouer sur les comportements et si l’image de l’automobile a évolué, elle conserve son attrait utilitaire, symbole d’indépendance et de liberté et demeure un objet essentiel dans les déplacements limitant le report vers d’autres modes. / As part of a longitudinal analysis focused on the Ile-de-France region, we approach the question of Peak Car, a research hypothesis that the cap on car use in many developed countries could be the sign of a long-term decline in automobile mobility.Using the data from the EGT and the Auto since the 1970s, we note that the limit on household mileage appeared in the early 1990s, followed by a continuous decline from 2000, and even now in the context of cheap fuel prices.In view of the Peak Car debate, we show that while fuel prices have played an important role in the reversal trend, other multidimensional factors are influencing. This is the case of the sharp decline in youth mobility. It also extends to the older age classes and could be the premise of a future change of use. Some engines of growth are also nearing completion and could reinforce the Peak Car: mobility between men and women is merging, the end of the increase in the mobility of retirees and the end social diffusion of the car. The decorrelation of the effect of income, synonymous with a saturation of the need for mobility, also takes place on motorisation. The merger of behaviour among income groups may reinforce this phenomenon.Finally, the role of opinion remains uncertain. Ecological consciousness does not seem to play on behaviour. And if the image of the automobile has evolved, it retains its useful appeal, symbol of independence and freedom and remains an essential object for trips limiting the transfer to others modes.

Many western countries have seen a plateau and subsequent decline in car travel during the early 21st century. What has generated particular interest and debate is the claim that the development cannot only be explained by changes in traditional explanatory factors such as GDP, fuel prices and land-use. Instead, it has been argued, the observed trends are indications of substantial changes in lifestyles, preferences and attitudes to car travel and thus, not just a temporary plateau but a true peak in car use. This thesis is a compilation of five papers, studying the issue on a national, international, regional and city scale through quantitative analysis of aggregate administrative data and individual travel survey data. It concludes that the aggregate development of car travel per capita can be explained fairly well with the traditional model variables GDP and fuel price. Furthermore, this thesis shows that spatial context and policy become increasingly important in car use trends: car use diverges over time between city, suburban and rural residents of Sweden and other European countries, while gender and to some extent income become less differentiating for car use. / <p>QC 20170918</p>

Uncertainty of outcome is widely recognised as a concern facing decision-makers and their advisors. In a number of spheres of policy, it appears uncertainty has intensified in the face of globalisation, economic instability, climate change, technological innovation and changing consumer preferences. How can planners and policymakers plan for an uncertain future? There is growing interest in, and use of, techniques that can help decision-making processes where deep uncertainty is involved. This paper is based upon one of the most recent international examples of a foresight exercise employed to examine uncertainty – specifically that which concerns uncertainty over the nature and extent of future demand for car travel. The principal focus of the paper is on the insights and guidance this examination of uncertainty brings forth for transport planning and policymaking. To accommodate deep uncertainty requires a flexible and open approach in terms of how policy and investment possibilities are formulated and judged. The paper argues for a focus upon the Triple Access System of spatial proximity, physical mobility and digital connectivity as a framework for policy and investment decisions that can harness flexibility and resilience. Uncertainty becomes an opportunity for decision-makers with the realisation that they are shaping the future rather than (only) responding to a predicted future. The paper outlines two forms of policymaking pathway: regime-compliant (in which adherence to trends and the nature of the world we have known pushes policy) and regime-testing (in which the nature of the world as we have known it is brought into question and vision pulls policy decisions). Stronger orientation towards regime-testing to assist in managing an uncertain future is advocated.

L’automobile occupe une place fondamentale dans notre société, au point qu’on a pu parler de « civilisation de l’automobile ». En dépit des critiques qui lui sont régulièrement adressées, celle-ci n’a cessé de se renforcer, avec toujours davantage de voitures par adulte et une proportion croissante de déplacements effectués en voiture. Cependant, depuis le tournant du millénaire, on assiste à un retournement de tendance. Pour la première fois, la mobilité en voiture baisse dans les grandes agglomérations, tandis que la circulation automobile plafonne à l’échelle nationale. Cette évolution, du reste, n’est pas spécifique à la France mais s’observe dans l’ensemble des pays développés, une tendance parfois désignée sous le terme de « peak car (travel) ». Parmi les explications les plus convaincantes de ce retournement, figurent l’augmentation du prix du carburant, suivie de la récession de 2008. La volonté des ménages de maîtriser leurs budgets-temps de transport y contribue également, dans un contexte d’allongement des déplacements vers le travail et de dégradation des vitesses de déplacements. En outre, la diffusion de l’automobile se rapproche de la saturation. Si à long terme, la croissance du kilométrage moyen par adulte est indexée sur le taux de motorisation, cependant à moyen terme l’utilisation des véhicules fluctue en fonction du pouvoir d’achat énergétique, et un modèle basé sur ces deux variables suggère qu’on observerait une réaction normale à une augmentation exceptionnelle du prix du carburant. Les facteurs de croissance du taux de motorisation tiennent eux-mêmes principalement à la succession de générations de plus en plus motorisées, surtout chez les femmes, compte tenu d’un accès de plus en plus large au permis de conduire, à l’activité professionnelle, et d’une urbanisation de plus en plus diffuse, qui ont augmenté le besoin d’une seconde voiture. Pour modéliser l’auto-mobilité, on propose une approche emboîtée, individuelle et longitudinale, segmentée en fonction du genre. L’auto-mobilité peut en effet être vue au niveau individuel comme une succession de choix emboîtés, puisque la détention du permis conditionne l’accès à un véhicule personnel, de même que la motorisation conditionne l’usage d’un véhicule. L’avantage d’une approche longitudinale réside dans la possibilité de distinguer entre mesures d’hétérogénéité et de sensibilité, qui ne sont pas équivalentes. Pour chaque niveau de choix, l’approche est structurée autour d’une analyse de type âge-cohorte-période. Globalement, les taux de motorisation sont plus hétérogènes chez les femmes, un résultat qui est susceptible de recevoir une double interprétation, économique ou sociétale. On peut le voir en termes d’inégalités de genre. Mais il peut également s’interpréter comme le reflet d’un statut encore intermédiaire du second véhicule, dont l’opportunité serait davantage évaluée au regard des besoins et des contraintes réels du ménage. A l’inverse, l’usage des véhicules est à la fois plus élevé et plus hétérogène chez les hommes, compte tenu de la fonction collective du véhicule principal et des arbitrages internes aux ménages quant aux choix du lieu de résidence et des lieux de travail des conjoints. Pour finir, on estime à partir de modèles sur données de panel des effets marginaux et des élasticités par rapport au revenu, au prix du carburant et à la densité, qui sont ensuite comparées avec la littérature. Dans l’ensemble, les résultats sont cohérents avec l’analyse descriptive, ainsi qu’avec la littérature. Le modèle permet également de rendre compte du déclin tendanciel des élasticités, traduisant l’approche de la saturation. Pour finir, une évaluation a posteriori confirme l’opportunité d’une modélisation séquentielle, indiquant que les choix de motorisation sont indépendants des niveaux d’usage de la voiture. / Car ownership and use are a decisive part of our society, which was sometimes designed as the “civilization of the car”. Despite many critics, the car has become ever-more central in the modern way of life, with an ever-increasing number of cars per adult and proportion of trips realized by car. However, from the beginning of the millennium, there was a reversal in the trend towards ever-more car use. For the first time, the average number of daily trips realized by car has been falling down in French conurbations, and nationwide traffic by car is leveling off. This situation, nonetheless, is not specific to France but is common to many developed countries, and is often referred to as the “peak car (travel)”. The main explanations for such a downturn include rising fuel prices from the late 1990’s, followed by the recession in 2008, but also household’s willingness to control their travel time budgets, in a context of increasing commuting distances and reduced travel speeds. Besides, the diffusion of car ownership is approaching saturation. While on the long-run, average car travel per adult is indexed on motorization, mid-term fluctuations of average car use per vehicle are related to the energetic purchasing power, and a simple model based on these two variables is suggesting that the stagnation of car use from the 2000’s could be a reaction of a usual kind to an exceptional rise in fuel prices. The growth in motorization is itself principally caused by the follow-up of ever-more motorized generations, especially among women, given their increasing access to driving license, job participation and ever-more diffuse land use patterns, which have increased the need for a second car within households. In order to model auto-mobility, a nested, individual and longitudinal approach is implemented, segmented by gender. Auto-mobility can indeed be seen as a follow-up of nested choices, as driving license is necessary for holding a car, while access to a personal vehicle is itself required for car use. The advantage of a longitudinal approach consists in the ability to distinguish between measures of heterogeneity and sensitivity, which can be shown not to be equivalent. For every given level of choice, the approach is based on an age-cohort-period-type analysis. Motorization rates happen to be more heterogeneous among women, a result which is likely to receive an interpretation either of a social or economic nature. According to the first interpretation, it should be regarded as the illustration of gender inequalities. However, it could also be regarded as reflecting the still-intermediary status of the second vehicle, which opportunity is assessed depending upon household’s specific needs and constraints. On the contrary, car use is at the same time higher and more heterogeneous among men, given the collective function of the first vehicle and household’s internal trade-offs in residential and job choices. Finally, average partial effects and elasticities are estimated from panel data models, either with respect to income, fuel prices or density. Generally, results are consistent with the descriptive part, as with the literature. The model also rationally gives account of the decreasing trend for elasticities, which was often noticed in the literature and reflects the approach of saturation. As a conclusion, an a posteriori evaluation of the assumption of a sequential decision process is made, confirming that choices of motorization and car use are mutually independent.