VISSIM Calibration for Urban Freeways, 2015

In urban areas, interchange spacing and the adequacy of design for weaving, merge, and diverge areas can significantly influence available capacity. Traffic microsimulation tools allow detailed analyses of these critical areas in complex locations that often yield results that differ from the generalized approach of the Highway Capacity Manual. In order to obtain valid results, various inputs should be calibrated to local conditions. This project investigated basic calibration factors for the simulation of traffic conditions within an urban freeway merge/diverge environment. By collecting and analyzing urban freeway traffic data from multiple sources, specific Iowa-based calibration factors for use in VISSIM were developed. In particular, a repeatable methodology for collecting standstill distance and headway/time gap data on urban freeways was applied to locations throughout the state of Iowa. This collection process relies on the manual processing of video for standstill distances and individual vehicle data from radar detectors to measure the headways/time gaps. By comparing the data collected from different locations, it was found that standstill distances vary by location and lead-follow vehicle types. Headways and time gaps were found to be consistent within the same driver population and across different driver populations when the conditions were similar. Both standstill distance and headway/time gap were found to follow fairly dispersed and skewed distributions. Therefore, it is recommended that microsimulation models be modified to include the option for standstill distance and headway/time gap to follow distributions as well as be set separately for different vehicle classes. In addition, for the driving behavior parameters that cannot be easily collected, a sensitivity analysis was conducted to examine the impact of these parameters on the capacity of the facility. The sensitivity analysis results can be used as a reference to manually adjust parameters to match the simulation results to the observed traffic conditions. A well-calibrated microsimulation model can enable a higher level of fidelity in modeling traffic behavior and serve to improve decision making in balancing need with investment.

Comportamentos de Risco no Tráfego Rodoviário

O presente trabalho descreve um estudo exploratório sobre a temática “Comportamentos de Risco no Tráfego Rodoviário” realizado a condutores da cidade de Bragança. Os principais objetivos direcionam-se para a identificação dos fatores cognitivos que mais influenciam a condução, das atitudes gerais e específicas de maior ou menor risco nos condutores de Bragança, e das crenças normativas e a intenção comportamental face à condução e aos comportamentos de risco. Para obter a informação necessária, foi usado o “Questionário baseado no modelo do Comportamento Planeado para a predição do comportamento de condução”, que foi realizado para a população portuguesa, e que a autora, Doutora Cristina Pimentão, permitiu a adaptação do mesmo ao tema da presente investigação. De uma forma geral, os resultados que se obtiveram evidenciam que o fator cognitivo que mais influencia o processo da condução é a atenção. Quanto às atitudes gerais, os comportamentos apontados que evidenciam maior risco são “A confiança na resposta do carro” e o “Excesso de confiança”, e os comportamentos que revelam menor risco são o cumprimento da regra de paragem completa num sinal de STOP e a discordância de que as pessoas que conduzem de forma agressiva estão mais atentas à condução. Por sua vez, nos resultados das atitudes específicas registam-se atitudes de indiferença, por parte dos inquiridos que responderam “Não concordo nem discordo” nas questões sobre “As campanhas que alertam para os efeitos do álcool são eficazes” e “Se o ensino das escolas de condução fosse adequado não teríamos condutores a conduzir sob a influência do álcool”. Já no que diz respeito às crenças normativas, verificaram-se resultados que apontam para expectativas de menor risco, pois na ótica dos condutores as pessoas que lhe são importantes esperariam deles comportamentos de menor risco. Paralelamente, os resultados sobre as intenções comportamentais traduzem baixas intenções de praticar o comportamento de risco, excetuando no item “É provável que eu venha conduzir um automóvel sob o efeito do álcool”, em que um número considerável de inquiridos respondeu que seria provável e muito provável a intenção de praticar este comportamento de risco. Os resultados são claros relativamente ao consumo de álcool e à sua influência no comportamento dos condutores, sendo necessário e urgente uma intervenção coerente e direcionada para a prevenção da ocorrência deste comportamento.

Behavioral Response to Environmental Taxation: Evidence from the Transportation Sector

This dissertation analyzes how individuals respond to the introduction of taxation aimed to reduce vehicle pollution, greenhouse gases and traffic. The first chapter analyzes a vehicle registration tax based on emissions of carbon dioxide (CO2), a major greenhouse gas, adopted in the UK in 2001 and subject to major changes in the following years. I identify the impact of the policy on new vehicle registrations and carbon emissions, compared to alternative measures. Results show that consumers respond to the tax by purchasing cleaner cars, but a carbon tax generating the same revenue would further reduce carbon emissions. The second chapter looks at a pollution charge (polluting vehicles pay to enter the city) and a congestion charge (all vehicles pay) adopted in 2008 and 2011 in Milan, Italy, and how they affected the concentration of nitrogen dioxides (NOx). I use data from pollution monitoring stations to measure the change between areas adopting the tax and other areas. Results show that in the first quarter of their introduction, both policies decreased NOx concentration in a range of -8% and -5%, but the effect declines over time, especially in the case of the pollution charge. The third chapter examines a trial conducted in 2005 in the Seattle, WA, area, in which vehicle trips by 276 volunteer households were recorded with a GPS device installed in their vehicles. Households received a monetary endowment which they used to pay a toll for each mile traveled: the toll varied with the time of the day, the day of the week and the type of road used. Using information on driving behavior, I show that in the first week a $0.10 toll per mile reduces the number of miles driven by around 7%, but the effect lasts only few weeks at most. The effect is mainly driven by a reduction in highway miles during trips from work to home, and it is strongly influenced by past driving behavior, income, the size of the initial endowment and the number of children in the household.

Relación entre estrés y desórdenes músculo esqueléticos en trabajadores de una empresa de transporte terrestre de pasajeros, Bogotá, 2015.

Introducción. Los conductores de transporte terrestre de pasajeros están expuestos a factores de riesgo inherentes a su labor, por lo que la intervención sobre estos factores es un aspecto relevante en las empresas de transporte público dado que dicha actividad afecta la calidad de vida de los mismos. Objetivo: Determinar la prevalencia de estrés en el lugar de trabajo y los factores de riesgo biomecánicos asociados en trabajadores de una empresa de transporte terrestre de pasajeros. Materiales y métodos: Estudio de corte transversal con datos secundarios procedentes de una población de 219 empleados, de los cuales 13 eran administrativos y 206 laboraban en la operación de una empresa de transporte terrestre de pasajeros. Las variables incluidas fueron socio demográficas, laborales, variables relacionadas con la medición de estrés y síntomas osteomusculares. El análisis estadístico incluyó medidas de tendencia central y dispersión y para identificar los factores asociados con el estrés se utilizaron pruebas de asociación Chi2 y prueba exacta de Fisher. Resultados: La edad promedio de los participantes fue de 43 años (DS 10 años), siendo en su mayoría trabajadores de sexo masculino (96,3%). Se presentaron síntomas y factores de riesgo biomecánicos en cuello y espalda en un 55.5%. Se encontró asociación significativa entre estrés con los síntomas en pies (p=0,009), con los factores de riesgo biomecánicos, se encontró relación significativa con el tiempo que permanece adoptando las posturas de inclinación hacia delante (p=0,000) y hacia atrás (p=0,001) de espalda/tronco y las posturas en muñecas, (p=0,000), y a la exposición de los conductores a superficies vibrantes (asientos de vehículo) (p=0,021). No se encontró asociación significativa entre estrés y la postura de sedente. Conclusiones: Con este estudio se encontró una prevalencia de estrés de 78% en el lugar de trabajo y de los factores de riesgo biomecánicos asociados a antigüedad, postura y repetitividad de movimientos, con repercusiones en cuello y espalda lumbar, por lo tanto, se requiere de un seguimiento a las condiciones de salud y trabajo para los empleados del sector transporte.

Examining Driver Behavior in Response to Work Zone Interventions: A Driving Simulator Study, 2010

Construction zones pose a significant threat to both workers and drivers causing numerous injuries and deaths each year. Innovations in work zone safety could reduce these numbers. However, implementing work zone interventions before they are validated can undermine rather than enhance safety. The objective of this research is to demonstrate how driving simulators can be used to evaluate the effect of various work zone interventions on driver performance.

National survey of speeding and other unsafe driving actions. Volume II: driver attitudes and behavior.

National Highway Traffic Safety Administration, Office of Research and Traffic Records, Washington, D.C.

National survey of drinking and driving attitudes and behavior: 1995. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

National survey of drinking and driving attitudes and behavior: 1997. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

National survey of drinking and driving: attitudes and behavior:1999. Volume 1: findings.

National Highway Traffic Safety Administration, Office of Research and Traffic Records, Washington, D.C.

National survey of drinking and driving: attitudes and behavior: 1999. Volume 2: methods report.

National Highway Traffic Safety Administration, Office of Research and Traffic Records, Washington, D.C.

National survey of drinking and driving: attitudes and behavior: 2001. Volume 1: summary report.

National Highway Traffic Safety Administration, Office of Research and Traffic Records, Washington, D.C.

National survey of drinking and driving attitudes and behavior: 1993. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Drinking-driving attitudes, knowledge and behavior: an analysis of the first four telephone surveys of the Fairfax Alcohol Safety Action Project. Final report.

National Highway Traffic Safety Administration, Washington, D.C.