جستجوی مقالات مرتبط با کلیدواژه « سرعت وسایل نقلیه » در نشریات گروه « محیط زیست »

noise from the vehicle aerodynamic effect, and noise from the interaction of the tire and the pavement. One of the most effective factors in creating tire/pavement sound and reducing the sound of reflection from the asphalt surface are: pavement texture, pavement life, vehicle speed, and temperature,pavement texture should have adequate sliding resistance at high speeds. Because one of the effective factors in reducing accidents and increasing safety is to improve the surface friction of the pavement. To evaluate the skid resistance of asphalt, the English pendulum test by EST3-74 ASTM standard in wet and dry conditions was used. T According to the results, it can be concluded that the preparation of pavements with a higher percentage of coarse grain, can increase friction by 32% and increase noise pollution by 6% due to the movement of vehicles. Increasing the speed also increases the pavement/tire noise by 0.9 dB. Compared to weather conditions (wet and dry asphalt), the slip resistance of wet asphalt decreased by 6%, and the amount of noise (pavement/rubber) in wet asphalt compared to dry asphalt increased by an average of 1 dB.

In the last decades, urban transportation systems and its effectes has attracted attention of researchers. The production of several dangerous pollutants caused by these systems has endangered human health in urban life. Analysis of average vehicle speed on pollutant enviromental is the main goal of this stud .The research method is descriptive – analytical and 22 areas of Tehran city is the region of this study. The used data in this research includes average vehicle speed and the information of urban transportation system have been used traffic police information bank and Tehran municipality yearbook. In this research at first, the average vehicle speed have been calculated for 22 areas of Tehran city separately in two different decades. In the next step, the production of three important pollutants, namely carbon monoxide, volatile gas and nitrogen oxide, have been investigated by vehicles and the level of cleanliness and pollution have been analyzed in different regions of Tehran and its causes. Investigations shows that the emissions of enviromental pollutants by vehicles is occurring at a certain range of speed. Increasing and reducing speed of this range, increases the production of pollutants from vehicles. Intelligent transportation system is the best idea to automatic control the transportation speed to reduce the pollution generation.