No abstract

As rodovias desempenham função importante no processo de estruturação das cidades, por facilitar os deslocamentos interurbanos. No entanto, quando absorvidas pela malha urbana de uma cidade, essas rodovias desenvolvem dinâmicas particulares com o espaço intraurbano no qual estão inseridas, com alterações na acessibilidade, na morfologia e no uso e ocupação da terra urbana. Com base nesse contexto, este artigo tem por objetivo analisar as dinâmicas entre a implantação do contorno rodoviário da BR-230 e o processo de produção do espaço intraurbano da cidade de João Pessoa-PB, entre os anos de 1963 e 2013, em termos de morfologia, uso e ocupação do solo urbano. O método empregado foi o da Lógica Evolutiva do Tecido Urbano, que divide a evolução urbana em três estágios: superação de limites, crescimento e combinação/conflitos. O método foi associado a ferramentas analíticas, como a Sintaxe Espacial e softwares de Sistema de Informação Geográfica. Os resultados mostram que a rodovia impulsionou o espraiamento da cidade para o setor sul e produziu uma malha urbana tentacular, onde também se identificou o padrão de crescimento horizontal e fragmentado, alterações na acessibilidade, uso do solo e na segregação socioespacial.

BackgroundTraffic noise is a highly relevant environmental impact in cities. Models to estimate traffic noise, in turn, can be useful tools to guide mitigation measures. In this paper, the applicability of models to estimate noise levels produced by a continuous flow of vehicles on urban roads is investigated. The aim is to identify which models are more appropriate to estimate traffic noise in urban areas since several models available were conceived to estimate noise from highway traffic.ResultsFirst, measurements of traffic noise, vehicle count and speed were carried out in five arterial urban roads of a brazilian city. Together with geometric measurements of width of lanes and distance from noise meter to lanes, these data were input in several models to estimate traffic noise. The predicted noise levels were then compared to the respective measured counterparts for each road investigated. In addition, a chart showing mean differences in noise between estimations and measurements is presented, to evaluate the overall performance of the models. Measured Leq values varied from 69 to 79 dB(A) for traffic flows varying from 1618 to 5220 vehicles/h. Mean noise level differences between estimations and measurements for all urban roads investigated ranged from −3.5 to 5.5 dB(A).ConclusionsAccording to the results, deficiencies of some models are discussed while other models are identified as applicable to noise estimations on urban roads in a condition of continuous flow. Key issues to apply such models to urban roads are highlighted.

This paper reports an adaptation for Brazilian conditions of the upgrade traffic flow rate criterion used by AASHTO in the Green Book to justify the need for a climbing lane. In the research reported in this paper, minimum flows that justify building of climbing lane were obtained through benefit/cost analyses. Costs were assumed to be the sum of construction and maintenance costs for the climbing lane. Benefits included the reduction of operational cost of vehicles and travel time after the construction of the climbing lane. The benefits were estimated from increasing in average upgrade speed and reductions of travel time and platoons in traffic. Data for the economic analyses were obtained of more than 20.000 simulations made using the TRARR simulator. The minimum flow that justifies the need for a climbing lane was assumed to be that for which the benefit/cost ratio equals one. The proposed criterion complements an adaptation of the AASHTO guidelines for climbing lanes to Brazil which, if applied, will increase the quality of service and safety on two-lane highways.

Recycled aggregates from solid waste can be used on pavements to minimize road construction costs and decrease environmental impacts related to the exploitation of natural resources and pollution. Thus, this study aimed to compare the mechanical performance of mixtures composed of natural aggregates, concrete recycled aggregates and polyethylene terephthalate (PET) flakes (in proportions from 0.5 to 4.0%) for application in granular pavement layers. Asphalt mixing, construction and demolition solid waste recycling, and PET recycling plants located in Joao Pessoa/PB, Brazil, provided the material used in this study. Tests such as particle size distribution, compaction with intermediate energy and California Bearing Ratio (CBR) were performed. The results of particle size distribution were useful to determine particle size proportions according to Brazilian DNIT specified standards and to prepare specimens for CBR tests. The compaction results indicated optimum water contents of 8.0 and 14.9%, and maximum dry densities of 2.01 and 1.83 g/cm3, for natural aggregates and recycled aggregates, respectively. Moreover, the optimum water contents increased between 16.4 and 17.7%, while the maximum dry densities decreased from 1.773 to 1.702 g/cm3 in mixtures of recycled aggregates and PET flakes, as PET proportions rose. Assessing mechanical resistance, the CBR value of natural aggregates resulted 45%, while that of recycled aggregates resulted 61%. On the other hand, the CBR results did not show a particular behavior tendency with the addition of recycled PET flakes. Therefore, it was possible to conclude that concrete recycled aggregates are technically viable for use in building granular pavement layers (sub-base and base) with low traffic flow, in spite of the variability of CBR results for mixtures of recycled aggregates and PET flakes.