بررسی تاثیر شرایط جوی و بارندگی بر سرعت جریان آزاد و ظرفیت تردد در آزاد راه‌ها: (مطالعه موردی آزاد راه تهران - قم)

بروجردیان, امین میرزا; ابراهیمی, مسعود

بررسی تاثیر شرایط جوی و بارندگی بر سرعت جریان آزاد و ظرفیت تردد در آزاد راه‌ها: (مطالعه موردی آزاد راه تهران - قم)

نوع مقاله : علمی - پژوهشی

نویسندگان

¹ استادیار، دانشکده عمران و محیط زیست، دانشگاه تربیت مدرس، تهران، ایران

² دانشجوی کارشناسی ارشد، دانشکده فنی و مهندسی، دانشگاه علوم و تحقیقات، دانشگاه آزاد اسلامی، واحد شاهرود، شاهرود، ایران

چکیده

تغییر شرایط پایه رانندگی موجب تغییر در ظرفیت عبوری آزادراه می‌شود که به معنای تغییر عملکرد و کیفیت سطح خدمت‌دهی راه است. عواملی که موجب کاهش ظرفیت می‌شود را می‌توان به دو دسته پایدار و ناپایدار تقسیم‌بندی کرد. در این تحقیق تاثیر عوامل جوی (بارندگی) بعنوان یکی از عوامل ناپایدار مؤثر بر سرعت جریان آزاد و ظرفیت در آزادراه تهران-قم بررسی می‌گردد تا بدین طریق مقدار ضریب کاهندگی بارش باران در منطقه جغرافیایی ایران که تاکنون مطالعه نشده، تعیین گردد و در صورتی که ساعت طرح سال آزادراهی در ساعت بارندگی قرار داشت، بابه‌کارگیری ضریب کاهندگی، ظرفیت طراحی تصحیح گردد. بدین منظور تغییرات سرعت جریان آزاد در در دو وضعیت جوی بارندگی و آفتابی مورد بررسی قرار گرفت و با استفاده از تجزیه و تحلیل رگرسیون چند جمله ای و اعتبار سنجی داده‌ها از طریق آزمون‌های آماری نتایج مورد ارزیابی قرار گرفتند. داده‌های ترافیکی و بارندگی مورد استفاده مربوط به 6 ماه انتهایی سال 1391 هستند. نتایج موید این نکته است که بارندگی باعث کاهش5/3 تا 9/8 درصدی ظرفیت و 4 تا 10 درصدی سرعت جریان آزادراه می‌شود.

کلیدواژه‌ها

20.1001.1.20086598.1396.8.4.1.0

عنوان مقاله [English]

A Survey On Weather Condition Effects on Free Flow Speed and Capacity in Freeways (Case Study: Tehran-Qom Freeway)

نویسندگان [English]

Amin Mirza Boroujerdian ¹
Masoud Ebrahimi ²

¹ Assistant professor, Department of Civil and Environmental Engineering, Tarbiat Modares University, Tehran, Iran

² MSc. Student, Faculty of Technology And Engineering, Research Sciences University, Shahrood, Iran

چکیده [English]

Decrease in traffic speed will result in freeway’s passing capacity, and this means decrease in performance level of service quality. Factors resulting in traffic speed decrease are categorized as permanent or temporary. Raining parse is one of temporary factors decreasing free flow speed. In this research effect of weather conditions (rainy weather) are surveyed as a temporary cause of decrease in capacity of freeway and on freeway’s free flow speed in Tehran-Qom freeway. So it can calculate the rain fall decrement index in the geographic region of Iran, (previously not calculated). If the time of traffic considered in design of freeway in the time of rain, by using decrement index the design capacity can be optimized.
In this research. In the beginning rainy hour and non-rainy hour were identified and separated, and also hours with less than 0.01 millimeter of rainfall due to insignificant effects were ruled out and considered as non-rainy hour .Studies show that light rain has no significant effect on flow speed and capacity and in some points its effects are neglected. But in case of heavy rainfall due to decrease in driver's vision range and decrease in surface friction between vehicle's wheels and road surface, flow speed will be significantly less than light rain situation and the changes between free flow speed of in 2 different conditions , rainy hour and sunny hour would be calculated. And with use of multi regression analysis and validating data from statistics test, result would be evaluated. traffic data and weather data from the last 6 months of hijri shamsi year 1391 in Tehran - Qom freeway was gathered and results obtained also confirms that rainy weather will result in 3.5 to 8.9 % decrease in capacity and 4 to 10% decrease in free flow speed.

کلیدواژه‌ها [English]

Free flow speed
Rainfall
Capacity
Freeway

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