Urban Traffic

The need for improved fuel economy for road vehicles has increased the interest in hybrid electric vehicle (HEV) and recovering vehicle energy. This paper aims to evaluate the amount of kinetic energy that could be restored through regenerative braking in a HEV. This work will not resort the Brazilian urban driving cycle NBR 6601, for this cycle does not fully represent a pattern of traffic faced regularly in urban areas, which is typically composed of heavy traffic and long periods of idleness. Therefore, a new drive cycle will be developed that better represents the Brazilian traffic. Also, considering the shortage of energy resources, the large amount of energy dissipated as heat during braking a vehicle is a recurring concern. Therefore, measuring the maximum available energy that could be restored through regenerative braking is the first step towards estimating the profit of using this technology and how it would pay off the investment in the long run. Thus, a longitudinal vehicle dynamics model is implemented using MATLAB/Simulink in order to simulate a small-size hybrid vehicle undergoing the cycle set up and assess the energy balance looking forward to the energy available for recovery.

This paper investigates the vulnerability of urban traffic networks to cyberattacks on traffic lights. We model traffic signal tampering as a bi-objective optimization problem that simultaneously seeks to reduce vehicular throughput in the network over time (maximize impact) while introducing minimal changes to network signal timings (minimize noticeability). We represent the Spatio-temporal traffic dynamics as a
static network flow problem on a time-expanded graph. This allows us to reduce the (non-convex) attack problem to a tractable form, which can be solved using traditional techniques used to solve linear network programming problems. We show that minor but objective adjustments in the signal timings over time can severely impact traffic conditions at the network level. We investigate network vulnerability by examining the concavity of the Pareto-optimal frontier obtained by solving the bi-objective attack problem. Numerical experiments are carried to illustrate the types of insights that can be extracted from the Pareto-optimal frontier. For instance, our experiments suggest that the vulnerability of a traffic network to signal tampering is independent of the demand levels.

Resumo: Analisamos as tendências da cidade contemporânea, de expansão e dispersão aliadas à mobilidade urbana, em um aglomerado urbano brasileiro, localizado no noroeste do Paraná, Brasil. Abordamos conceitos de cidade difusa, de dispersão e de fragmentação urbana refletindo sobre as tendências de conformação regional e o papel da mobilidade urbana. Para tanto, investigamos a história da formação do território, analisamos mapeamentos de uso do solo, os eixos regionais e dados de população, de frota e de deslocamento populacional. Observamos que o município polo concentra as atividades econômicas e os movimentos pendulares, cada vez mais dependentes do transporte individual de passageiros. Com a instalação de grandes polos de atração em áreas periféricas, a partir de fluxos regionais que produzem novas centralidades, percebe-se a tendência de abandono do forte caráter polarizador para relações de fluxos mais horizontais.
Palavras-chave: tráfico urbano, descentralização urbana, planificação regional, migração pendular, Brasil.
Resumen: Analizamos las tendencias de la ciudad contemporánea de expansión y dispersión, aliadas a la movilidad urbana, en un aglomerado urbano brasileño situado en el noroeste de Paraná, Brasil. Abordamos conceptos de ciudad difusa, dispersión y fragmentación urbana, reflexionando sobre las tendencias de conformación regional y el papel de la movilidad urbana. Para ello, investigamos la historia de la formación del territorio, analizamos mapeos de uso del suelo, los ejes regionales y los datos de población, flota y desplazamiento poblacional. Observamos que el municipio polo concentra las actividades económicas y los movimientos pendulares, cada vez más dependientes del transporte individual de pasajeros. Con la instalación de grandes polos de atracción en áreas periféricas, a partir de flujos regionales que producen nuevas centralidades, se percibe la tendencia al abandono del fuerte carácter polarizador por relaciones de flujos más horizontales.
Palabras clave: tráfico urbano, descentralización urbana, planificación regional, migración pendular, Brasil.
Abstract: We analyze the trends of the contemporary city of expansion and dispersion allied to urban mobility, in a Brazilian urban cluster located in the Northwest of Paraná, Brazil. We approach concepts of diffuse city, dispersion and urban fragmentation reflecting on the regional conformation tendencies, and the role of urban mobility. To do so, we investigated the history of territory formation, analyzed land use mappings, regional axes, and population, fleet, and population displacement data. We observed that the polo municipality concentrates the economic activities and the commuting movements, increasingly dependent on individual passenger transportation. With the installation of large poles of attraction in peripheral areas, from regional flows that produce new centralities, one can perceive the tendency of abandoning the strong polarizing character to relations of more horizontal flows.
Keywords: urban traffic, urban decentralization, regional planning, commuting, Brazil.
Résumé: Nous analysons les tendances de la ville contemporaine en expansion et en dispersion, alliées à la mobilité urbaine dans un groupe urbain brésilien situé au nord-ouest de Paraná, au Brésil. Nous abordons les concepts de ville diffuse, dispersion et de fragmentation urbaine reflétant les tendances de la conformation régionale, et le rôle de la mobilité urbaine. Pour ce faire, nous avons étudié l’historique de la formation du territoire, analysé les cartographies de l’utilisation des sols, les axes régionaux et les données sur la population, la flotte et les déplacements de population. Nous avons observé que la municipalité de polo concentre les activités économiques et les déplacements domicile-travail, de plus en plus dépendants du transport de passagers individuel. Avec l’installation de grands pôles d’attraction dans les zones périphériques, à partir de flux régionaux qui produisent de nouvelles centralités, on peut percevoir la tendance à abandonner le fort caractère polarisant au profit de relations de flux plus horizontaux.
Mots-clés: circulation urbaine, décentralisation urbaine, planification régionale, migration alternante, Brésil.