Margarida C Coelho

Measuring and Modeling Emission Effects for Toll Facilities

At conventional pay tolls, vehicles joining a queue must come to a stop and undergo several stop-and-go cycles until payment is completed. As a result, emissions increase because of excessive delays, queuing, and speed change cycles for approaching traffic. The main objective of this research is to quantify traffic and emission impacts of toll facilities in urban corridors. As a result of experimental measurements of traffic and emissions, the impact of traffic and emission performance of conventional and electronic toll facilities is presented. The approach attempts to explain the interaction between toll system operational variables (traffic demand, service time, and service type) and system performance variables (stops, queue length, and emissions). The experimental data for validating the numerical traffic model were gathered on pay tolls located in three main corridors that access the city of Lisbon, Portugal. The emissions model is based on real-world onboard measurements of vehicle emissions. With the appropriate speed profiles of vehicles in pay tolls, onboard emission measurements were carried out to quantify the relationships between vehicle dynamics and emissions. The main conclusion of this work is that there are two different types of stop-and-go driving cycles for vehicles joining the queue at a conventional toll booth: short and long. The length of each cycle depends on the expected queue length at the toll booth and the frequency of each cycle directly affects the level of vehicle emissions. The greatest percentage of emissions for a vehicle that stops at a pay toll is due to its final acceleration back to cruise speed after leaving the pay toll.

Analysis Of The Environmental Impact Of Urban Buses: Application To A Case Study In Lisbon

The paper provides information on a study of the environmental impact of urban buses in a real inner city situation. The CORINAIR methodology was applied to investigate emissions and fuel consumption of urban buses on two different routes in Lisbon. Bus dynamic performance and terrain topography along the selected routes were characterized experimentally. The paper identifies the differences in the selected routes in relation with topography, average and instantaneous speed, number of stops and the number of passengers. Conclusions are also presented.

Assessment of Corridors with Different Types of Intersections: Environmental and Traffic Performance Analysis

Recently, roundabouts in a series have been installed along corridors to enhance road safety. However, the benefits of this traffic-calming technique on traffic performance and pollutant emissions compared with other forms of intersections, such as traffic lights and stop-controlled solutions, are not properly known. This study used a microscopic approach to evaluate the effects of a corridor with four roundabouts on traffic performance and emissions, in comparison with traffic lights and stop-controlled solutions. Average travel time and number of vehicle stops were used as measures of traffic performance; carbon dioxide, monoxide carbon, nitrogen oxides, hydrocarbons, and particulate matter were used to quantify emissions. The traffic and emissions performance of each solution was evaluated on three levels: (a) arterial, (b) intersection, and (c) morning peak versus evening peak periods. It was found that, regardless of the time period, traffic lights in corridors at the arterial level produced higher total emissions (> 6%), while stop-controlled intersections produced lower emissions (≈12%) compared with roundabouts, mainly because of unbalanced traffic flows between main and minor roads. The results for traffic performance showed advantages in implementing roundabouts when the main concern was the number of vehicle stops. At the intersection level, an emissions improvement (between 2% and 14%) was observed at traffic lights on four-leg intersections.

Statistical and Semi-Dynamical Road Traffic Noise Models Comparison with Field Measurements

The need for road traffic noise monitoring is growing in urban areas due to the growth of vehicles number and to the consequent increase of risk for human health. Noise measurements cannot be performed everywhere, or even in a large number of sites, because of high costs and time consumption. For this reasons, Road Traffic Noise predictive Models (RTNMs) can be implemented to estimate the noise levels at any distance, knowing certain parameters needed as input of the RTNM. In this paper, the main statistical RTNMs are presented, together with the implementation of two innovative and advanced models: the EU suggested model (CNOSSOS-EU) and a research model presented by Quartieri et al. (2010). These models will be compared with noise measurements performed in different sites and with different traffic conditions, in order to avoid bias from geometry or other features of the area under study. The main conclusion is that the application of innovative models and the inclusion of dynamical information about traffic flow, will lead to better results with respect to statistical models.

Micronucleus frequencies in lymphocytes and buccal cells in formaldehyde exposed workers

Formaldehyde (FA) is a high-volume production chemical produced worldwide with a large range of industrial and medical uses. Listed, since 2004, by IARC as a human carcinogen, FA status was recently revised by the US government who reclassified this compound as known to be a human carcinogen. Both reclassifications are based on sufficient evidence of carcinogenicity from epidemiologic studies, supporting data on mechanisms of carcinogenesis and experimental evidence in animals. The highest level of human exposure to FA occurs in occupational settings. Consistent findings of increased risks of certain types of rare cancers were found among workers with higher measures of exposure to FA (exposure level or duration). The aim of the present study was to assess the genotoxic effects of occupational exposure to FA. A group of pathology and anatomy workers was evaluated for micronuclei in lymphocytes and in exfoliated buccal cells. Genotoxic endpoints are of great interest in the risk assessment of occupational carcinogens because they precede by a long time the potential health effects, thus offering a greater potential for preventive measures. Micronuclei in lymphocytes and in exfoliated buccal cells were significantly higher in the exposed subjects when compared with controls. Air sampling was performed in the workers’ breathing zone for representative working periods and an 8h-time weighted average was assessed. Results