No abstract

Resumo: Este trabalho apresenta uma análise exploratória das variáveis que contribuem na modelagem da segurança viária ao nível estratégico e tático de planejamento. A princípio, uma base de dados geográficos de 126 zonas de tráfego é compilada a partir de dados socioeconômicos disponíveis, características da rede e dos acidentes georreferenciados. Visando separar os efeitos parciais das variáveis sobre a ocorrência de acidentes, a análise compreende: i) uma análise fenomenológica e de correlação que resultou na redução de variáveis preditoras, e ii) uma análise de regressão binomial negativa, que identificou os preditores significativos. Dada a natureza espacial dos dados geográficos, a suposição de independência espacial entre erros modelados é analisada. Os resultados confirmaram que os acidentes estão relacionados com a renda e atividade econô-mica, no nível estratégico, e a atributos físicos e de operação da rede, no nível tático. A evidência da dependência espacial no nível estratégico aponta direções para trabalhos futuros.Palavras-chave: modelagem de segurança viária, modelos lineares generalizados, autocorrelação espacial. Abstract:This study presents an exploratory analysis of the variables that may contribute to modeling of road safety at the strategic and tactical planning level. At first, a geographic database of 126 traffic zones is compiled from available socioeconomic datasets, roadway data and geocoded accidents. Aiming to correctly partial out the effects of each variable on accident frequency, the analysis comprises: i) a phenomenological and correlation analysis that yielded a reduced set of predictor variables, and ii) a Negative Binomial regression analysis that identified the significant predictors. Given the spatial nature of geographic data, the assumption of spatial independence between model errors is analyzed. The results confirmed that accidents are related to income and economic activity, at strategic level, and physical and operation attributes of the roadway system, at the tactical level. The evidence of spatial dependence at the strategic level points to directions for further work.Keywords: road safety modeling, generalized linear models, spatial auto-correlation. INTRODUÇÃOO processo de planejamento de transporte, em nível estratégico, tem estado bastante voltado para a modelagem de cenários e avaliação de alternativas levando em consideração medidas de desempenho relacionadas à fluidez do sistema. Entretanto, observa-se que, apesar de sua reconhecida importância, o Desempenho da Segurança Viária (DSV) não está incorporado de forma objetiva e sistemática nesse processo de planejamento (ITE, 2009).Acredita-se, pelo menos em parte, que a discrepância entre as dimensões de fluidez e segurança viária no processo de planejamento podem estar associadas aos desafios relacionados à coleta de informações e consolidação dos bancos de dados de acidentes de trânsito e em decorrência da natureza estocástica do fenômeno. Ressalta-se ainda que, os esforços de modelagem do DSV, principalmente ...

-Anaerobic digestion is an important alternative for domestic wastewater treatment, especially in warm climate regions. Two full-scale anaerobic schemes were investigated: septic tank combined with anaerobic filter (S T A NF ) and conventional UASB reactors. Treated effluents from these systems were subjected to disinfection by chlorination. The operational performance of 56 full-scale plants (36 S T A NF and 20 UASB) provided a realistic view. Findings showed that the plants operated with low OLR (< 2.0 kg COD/m 3 .day). Despite this, the removal of organic material was below values suggested by the literature (around 60% for COD). A removal of 4.0 Log 10 units of total coliform and E. coli can be reached with residual chlorine (R CL ) of at least 2.0 Cl-Cl 2 /l. Although UASB plants have performed better, improvement of maintenance is needed in both treatment configurations.

No abstract

In Brazil, pedestrians represent the third largest group of crash victims, after motorcyclists and car occupants. Implementing measures to ensure pedestrian safety and prioritization requires an understanding of the risk factors associated with crash injuries. In this study, a random-parameter logit model was estimated to investigate factors influencing the severity of crashes with pedestrians in urban roads in Fortaleza, Brazil. A sample of 2,660 observations of crashes with pedestrians in the city from 2017 to 2019 was used. The injury severity levels adopted by the Crash Information System (SIAT) were grouped into three categories: mild/moderate, severe and fatal. From the investigated factors, only the variable related to the pedestrian's age over 60 years old obtained a significant random parameter. In this case, the heterogeneity in the observations may be associated, among other factors, to the body’s physical fragility and the cognitive function that may differ among individuals in this group. The results showed that the driver’s gender and age, the crash site, the motorcycle use, and the presence of speed cameras did not have a significant impact on the severity of crashes with pedestrians. On the other hand, crashes occurring at night, with heavy vehicles, on weekends, and located on roads with higher traffic classification are associated with more severe injuries. The incorporation of unobserved heterogeneity in the estimation of the model's parameters stands out as one of the main contributions of this work.