Cette thèse s'intéresse aux fondements du comportement des usagers face à la congestion dans les transports publics. Elle se compose de trois essais distincts. Les deux premiers essais examinent l'adaptation des usagers au manque de ponctualité et à l'inconfort. Le troisième essai offre une analyse empirique de l'effet « foule ». Dans le premier chapitre, je présente un modèle de compétition bimodale entre une ligne de transport public sujette aux retards, et un mode alternatif. A l'équilibre du marché, le niveau de fiabilité choisi par la firme en charge des transports publics augmente avec le prix du mode alternatif via un effet « demande » évoquant l'effet Mohring. L'étude de la qualité de service optimale montre que souvent, la fiabilité des transports publics et donc leur fréquentation à l'équilibre sont inférieurs à ce qu'ils seraient à l'optimum social. Dans le second chapitre, afin d'étudier le coût de l'inconfort et ses implications quant au choix de l'heure de déplacement, je développe un modèle structurel dans lequel les usagers des transports public choisissent entre voyager dans un véhicule bondé et arriver à destination à l'heure désirée ou alors voyager plus tard ou plus tôt pour éviter la foule. J'établis la distribution des usagers parmi les véhicules à l'équilibre et à l'optimum social, et montre que l'optimum social peut être décentralisé par une tarification fine par véhicule. Les propriétés du modèle sont comparées avec celles du modèle du « bottleneck » et des modèles de congestion routière. Dans le troisième chapitre, j'analyse l'influence de la densité d'usagers sur la satisfaction liée au confort durant un déplacement en transport public. De plus, je décris l'anatomie de l'effet « foule » en testant différents aspects (odeur, bruit, position debout...) comme des causes d'inconfort lorsque la densité d'usagers augmente. J'identifie un net effet « foule » : en moyenne, un usager supplémentaire par mètre carré diminue de 1 la satisfaction liée au confort qui est mesurée sur une échelle de 0 à 10. Je ne trouve pas de corrélation entre temps de transport et l'effet « foule ». Cependant, cet effet augmente avec le revenu des usagers. Trois causes de désutilité liée à la foule sont identifiées : une plus grande probabilité de devoir voyager debout, un usage limité du temps, et des conditions de déplacement plus bruyantes. Ces désagréments sont plus importants chez les femmes et les usagers les plus aisés. / This dissertation addresses the foundations of user’s behavior with respect to the congestion in public transport. It is made of three distinct essays. The two first essays investigate how users get used to lack of punctuality and crowding. The third essay presents an empirical analysis of the crowding effect. In the first chapter, I consider the modeling of a bi-modal competitive network involving a public transport mode, which may be unreliable, and an alternative mode. The public transport reliability set by the public transport firm at the competitive equilibrium increases with the alternative mode fare, via a demand effect. This is reminiscent of the Mohring Effect. The study of the optimal service quality shows that often, public transport reliability and thereby patronage are lower at equilibrium compared to first-best social optimum. In the second chapter, to study the behavioral implications and costs of crowding, I develop a structural model in which public transport users face a choice between traveling in a crowded train and arriving when they want, and traveling earlier or later to avoid crowding but arriving at an inconvenient time. I derive the user equilibrium and socially optimal distribution of passengers across trains, show how the optimum can be decentralized using train-specific fares, and characterize the welfare gains from optimal pricing. Properties of the model are compared with those obtained from the bottleneck and flow congestion models of road traffic. In the third chapter, I investigate the influence of in-vehicle crowding on the comfort satisfaction experienced during a public transport journey. Moreover, I describe the anatomy of the crowding effect by testing various nuisance factors (Smell, Noise, Standing...) as channels through which crowding may decrease the comfort satisfaction. I find a clear crowding effect: on average, an extra-user per square meter decreases by one the expected 0 to 10 scale individual well-being. I do not find any empirical evidence of this effect being intensified by the travel time. However, the crowding effect increases with the income of users. I find three causes of crowding disutility: a higher probability to stand for all or part of the journey, a poorer use of the time during the journey, and noisier travel conditions. These features of discomfort matter more for women and wealthy individuals.

We propose a distributed, collaborative traffic congestion detection and dissemination system using VANET that makes efficient use of the communication channel, maintains location privacy, and provides drivers with real-time information on traffic congestions over long distances. The system uses vehicles themselves, equipped with simple inexpensive devices, as gatherers and distributors of information without the need for costly road infrastructure such as sensors, cameras or external communication equipment. Additionally, we present a flexible simulation and visualization framework we designed and developed to validate our system by showing its effectiveness in multiple scenarios and to aid in the research and development of this and future VANET applications. / by Francisco M. Padron. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Cheung, Kin Tai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 34-35). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.iii / Contents --- p.iv / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Literature Review --- p.4 / Chapter 3 --- Data Description --- p.7 / Chapter 4 --- Ordinary Least-Squares and Fixed-Effect Estimations --- p.10 / Chapter 4.1 --- OLS Estimation --- p.10 / Chapter 4.2 --- Fixed-Effect Estimation --- p.13 / Chapter 5 --- Cross-sectional and Fixed-Effect IV Estimations --- p.16 / Chapter 5.1 --- Cross-sectional IV Model --- p.16 / Chapter 5.2 --- Fixed-Effect IV Model --- p.23 / Chapter 6 --- Conclusion --- p.29 / Appendix --- p.30 / Estimation Results for Honshu Island --- p.30 / Ordinary-Least Squares Results in 150 observations regression --- p.33 / References --- p.34

Smart communications devices are giving users instant access to applications that consume large amounts of data. These applications have different requirements on the network for delivery of data. In order to support these different applications, operators are required to support multiple service classes. Given the regulatory and technology constraints and the relatively high cost associated with wireless spectrum licensing and utilization, demand will exceed supply leading to congestion and overload conditions. In addition to new broadband radio technologies offering higher data rates, operators are looking at deploying alternate heterogeneous technologies, such as WLAN, to provide additional bandwidth for serving customers. It is expected that this will still fall short of providing enough network resources to meet the ITU requirement for 1% new call blocking probability. An economic mechanism that offers incentives to individuals for rational behavior is required in order in order to reduce the demand for network resources and resolve the congestion problem. The research in this dissertation demonstrates that the integration of a dynamic pricing with connection admission control mechanism for an operator deploying cooperative heterogeneous networks (e.g., LTE and WLAN) offering multiple QoS service classes reduces the new call blocking probability to the required 1% level. The experimental design consisted, first, of an analytical model of the CAC algorithm with dynamic pricing in a heterogeneous environment. The analytical model was subsequently validated through discrete-event simulation using Matlab.

Transmission Control Protocol (TCP) is considered one of the most important protocols in the Internet. An important mechanism in TCP is the congestion control mechanism which controls TCP sending rate and makes TCP react to congestion signals. Nowadays in heterogeneous networks, TCP may work in networks with some links that have lossy nature (wireless networks for example). TCP treats all packet loss as if they were due to congestion. Consequently, when used in networks that have lossy links, TCP reduces sending rate aggressively when there are transmission (non-congestion) errors in an uncongested network. One solution to the problem is to discriminate between errors; to deal with congestion errors by reducing TCP sending rate and use other actions for transmission errors. In this work we investigate the problem and propose a solution using an end-to-end error discriminator. The error discriminator will improve the current congestion window mechanism in TCP and decide when to cut and how much to cut the congestion window. We have identified three areas where TCP interacts with drops: congestion window update mechanism, retransmission mechanism and timeout mechanism. All of these mechanisms are part of the TCP congestion control mechanism. We propose changes to each of these mechanisms in order to allow TCP to cope with transmission errors. We propose a new TCP congestion window action (CWA) for transmission errors by delaying the window cut decision until TCP receives all duplicate acknowledgments for a given window of data (packets in flight). This will give TCP a clear image about the number of drops from this window. The congestion window size is then reduced only by number of dropped packets. Also, we propose a safety mechanism to prevent this algorithm from causing congestion to the network by using an extra congestion window threshold (tthresh) in order to save the safe area where there are no drops of any kind. The second algorithm is a new retransmission action to deal with multiple drops from the same window. This multiple drops action (MDA) will prevent TCP from falling into consecutive timeout events by resending all dropped packets from the same window. A third algorithm is used to calculate a new back-off policy for TCP retransmission timeout based on the network's available bandwidth. This new retransmission timeout action (RTA) helps relating the length of the timeout event with current network conditions, especially with heavy transmission error rates. The three algorithms have been combined and incorporated into a delay based error discriminator. The improvement of the new algorithm is measured along with the impact on the network in terms of congestion drop rate, end-to-end delay, average queue size and fairness of sharing the bottleneck bandwidth. The results show that the proposed error discriminator along with the new actions toward transmission errors has increased the performance of TCP. At the same time it has reduced the load on the network compared to existing error discriminators. Also, the proposed error discriminator has managed to deliver excellent fairness values for sharing the bottleneck bandwidth. Finally improvements to the basic error discriminator have been proposed by using the multiple drops action (MDA) for both transmission and congestion errors. The results showed improvements in the performance as well as decreases in the congestion loss rates when compared to a similar error discriminator.

published_or_final_version / Urban Planning / Master / Master of Science in Urban Planning

This dissertation focuses on two main research questions related to the effect of a factor in a local labor market. Both relate to a finding of Black et al. (2014) that married women are less likely to work in Metropolitan Statistical Areas (MSAs) with more traffic congestion. The first essay evaluates the appropriateness of an MSA as a geographical entity in estimating the effect of congestion on labor supply of married women. One concern with such aggregated data is that they do not take into account within-city variation in congestion. In order to address this issue, I replicate the works by Black et al. (2014) at smaller geographical levels. Once the coefficient on commute time at each level is estimated, I compare the coefficients from smaller geographical entities with one from the MSA to examine if they are statistically similar. I find that an MSA is a geographically proper unity when the effect of commute time on the LFP of married women is examined. Additionally, I explore whether commuting time has also a significant effect on other related to labor market issues. First, I find longer commuting time is associated with shorter weekly working time of high school educated women. Secondly, fewer married women are self-employed in the area with longer commuting time. The second essay begins with the possibility of correlation between congestion and the error term in the estimation equation by Black et al. (2014). The coefficient on congestion in their equation might be biased due to the endogeneity problem. I employ a structural approach with a multinomial logit in order to deal with the endogeneity issue. By examining the effect of congestion and its interaction term on city-specific fixed effects that can be estimated using a discrete-choice model of residential decision, I find that the negative relationship between congestion and labor supply of married women discovered by Black et al. (2014) is partially true. The effect of congestion is statistically uncertain or depends on the model specifications, with the exception of a finding that married women with children are especially responsive to the effect of traffic congestion on their willingness to work.

Traffic congestion is a significant cost to society, amounting to somewhere between 1 and 2% of GDP according to an EU-wide survey (CE Delft, 2011). To address this cost, road pricing has long been viewed as the first best solution although issues with public and political acceptance have meant the uptake of such schemes has been low. In the meantime parking policies, a second best alternative to road pricing, have become extensively used by local authorities as a means of managing congestion due to the influence the price and availability of parking can have on a motorist s decision to drive. The effectiveness of such strategies however is limited due to local authorities being unable to control privately owned parking. More specifically, free parking at the workplace is seen as contributing to congestion at peak times by incentivising drivers to commute to work by car. To address this, in the UK the Transport Act 2000 granted powers to local authorities to introduce a Workplace Parking Levy (WPL) whereby employers are required to pay a sum based on the number of parking spaces they provide for their staff with the revenue hypothecated for local transport improvements. The introduction of such powers meant the Government estimated there would be 12 schemes by 2010. To-date however, only Nottingham has introduced a WPL. The aim of this thesis therefore is to investigate the transferability of the WPL to other local authorities which is analysed through the application of the Policy Transfer Framework to the WPL in the UK context. It focuses on the views of key stakeholders with respect to the WPL at both the national and local authority level so as to understand the reasons for the low uptake as well as the design, implementation and operational considerations required to introduce such a scheme. The conclusions of this thesis are that lessons can and have been learnt with respect to introducing a WPL as the findings reveal that Nottingham City Council (NCC) drew on aspects of Policy Transfer to facilitate the introduction of the scheme. Specifically, NCC Councillors developed a vision of what a WPL could deliver and were reassured by experts from abroad whilst a staff transfer exercise allowed officers to learn lessons in terms of how the scheme should be designed, implemented and operated. What s more, lessons from a formal DfT evaluation of the pilot scheme in Nottingham following the delivery of the full WPL package will have a significant influence (either positive or negative) on the number of future schemes. More broadly, the results suggest that the WPL is transferable and the adoption of additional WPL schemes in the future is likely. This is due in no small part to the fact that the Nottingham scheme has so far enjoyed a relatively painless introduction even though it is still too early to evaluate how successful it has been in meeting its objectives. This research has made a significant contribution to knowledge in that it has explored the WPL with key stakeholders to generate a standard for introducing and operating a WPL. It has also provided an application of the Policy Transfer framework to understand the process and development of a new policy as well as the type and where lessons are learnt.

Por muitos anos, a ciência tratou todas as redes como se seus relacionamentos fossem estabelecidos de forma randômica, ou seja, a maioria dos nós teriam aproximadamente o mesmo número de relacionamentos. Porém, o mapeamento de uma variedade de sistemas revelou que a maioria dos nós tinha poucos relacionamentos, enquanto alguns nós têm uma grande quantidade de conexões. Processos microscópicos dinâmicos e estatísticos são duas facetas de sistemas complexos, que estão intimamente ligadas, e a compreensão da sua interdependência é importante tanto para a previsão quanto planejamento estratégico. Os exemplos mais proeminentes incluem o ruído do tráfego em redes de comunicação, sinais ruidosos em sistemas desordenados e auto-organizados, e as séries temporais das flutuações dos preços nos mercados financeiros. Neste trabalho foram analisadas não apenas características globais do tráfego de pacotes em redes complexas, como a presença ou não de congestionamento na rede como um todo, mas também as características locais (isto é, de roteadores específicos) do tráfego no ponto de transição entre a fase livre e a fase de congestionamento. Os resultados mostram, entre outros, que a transição de um estado livre de congestionamento para o estado congestionado de um nó ocorre quando o coeficiente de detrended fluctuation analysis da série temporal do número de pacotes na fila de espera do nó é próximo do valor crítico de 1. / For many years the science networks all treated as if their relationships were set at random, that is, most of us have approximately the same number of relationships. However, the mapping in a variety of systems revealed that most of us had a few relationships, while some of us have a lot of connections. Dynamic and statistical microscopic processes are two facets of complex systems, which are closely linked, and understanding of their interdependence is important both for predicting as strategic planning. Prominent examples include traffic noise in communication networks, noisy signals in disordered systems and self-organized, and the time series of price fluctuations in financial markets. This work analyzed not only the overall characteristics of package traffic in complex networks and the presence or absence of congestion on the network as a whole, but also the local characteristics (ie, specific routers) of the traffic at the point of transition from the free phase, and congested phase. The results show, among others, that the transition from free to congested traffic in a node happens when the detrended fluctuation analysis coefficient of the time series of the number of waiting packets is close to the critical value of 1.

O presente trabalho analisa e discute a crise de mobilidade cotidiana nas duas últimas décadas, em São Paulo, tendo em vista o agravamento gradativo das condições de circulação viária na metrópole paulistana. Considerando o espaço como produto, condição e meio de reprodução das relações sociais, defendemos a tese de que a atual crise da mobilidade cotidiana advém de um conjunto de medidas que foram formuladas e implantadas através de políticas econômicas de orientação neoliberal, com destaque para os novos meios de financiamento à produção do espaço urbano e à reorganização produtiva da indústria automobilística nacional, bem como para as estratégias voltadas ao incentivo do consumo de bens duráveis, viabilizado pela ampliação das linhas de crédito para a aquisição de bens duráveis, principalmente carros. A esses elementos associam-se outros, tais como: a extensão e a densidade da ocupação urbana, a baixa qualidade dos sistemas de transportes coletivos e o traçado da infraestrutura viária. A apreciação conjunta desses elementos constitui o quadro a partir do qual realizamos nossa análise / This dissertation analyzes and discusses the crisis of daily mobility in the past two decades in São Paulo, caused by the gradual worsening of the conditions of road circulation in the metropolis. Regarding space as a product, a condition and a means of the reproduction of social relations, we put forth the hypothesis that the current crisis of mobility is the outcome of a number of actions that were formulated and implemented as part of neoliberal economic policymaking. Among such actions are the new sources of credit for the production of urban space, the restructuring of the domestic automobile industry and the strategies that encourage the purchase of durable goods (especially cars) made possible by the expansion of consumer credit. Other elements combine with these three basic causes, such as the low quality of public transit systems and the road layout. By taking account of all these elements together, we build the framework upon which we carry out our analysis