ارزیابی تاثیر ایمنی میدان در کاهش تصادفات تقاطع

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانش آموخته کارشناسی ارشد، دانشکده مهندسی‌عمران، دانشگاه پیام نور، تهران، ایران

2 گروه مهندسی عمران، دانشگاه پیام‌نور، تهران، ایران

10.22034/tri.2022.84262

چکیده

تعیین مقدار عددی اثربخشی ایمنی اقدامات اصلاحی یا ضریب بهبود تصادف (CMF) یکی از موضوعاتی است که در سال‌های اخیر در دنیا توجه زیادی به آن شده است. در این خصوص مطالعات متعددی به منظور تعیین CMF مربوط به تبدیل تقاطع به میدان در کشورهای مختلف صورت گرفته است. نتایج این مطالعات، کاهش حدود 35 تا 70 درصدی تصادفات در تقاطع‌ها بوده است. از آنجاییکه در ایران مطالعه‌ای جدی در خصوص تعیین CMF احداث میدان و درصد کاهش تصادف ناشی از این اقدام اصلاحی انجام نشده، محققان در این پژوهش به دنبال تعیین CMF و درصد کاهش تصادفات ناشی از این اقدام در ایران هستند. برای نیل به این هدف، میدان سلمان فارسی شهر ایلام مورد ارزیابی قرار گرفت. میزان AADT از ترددشمارهای موجود و داده‌های تصادف از پلیس راهور اخذ شد. برای تعیین CMF روش بیزتجربی در نظر گرفته شد. دلیل استفاده از روش بیزتجربی، کارایی بالای آن در حذف پدیده رگرسیون به میانگین و دیگر عوامل مخدوش کننده زمانی بوده و دقت بالای این روش به دلیل استفاده از تابع عملکرد ایمنی (SPF) به منظور تخمین منطقی فراوانی تصادفات در دوره قبل از اقدام اصلاحی است. در روند مطالعه، یک تابع عملکرد ایمنی از AASHTO(2010) بکارگرفته شد. با استفاده از این ابزار و پیشبینی تصادفات قبل و بعد از احداث میدان و همچنین محاسبه فراوانی تصادفات مورد انتظار در دوره قبل و بعد، اثربخشی ایمنی محاسبه شد. مقدار CMF بدست آمده در این تحقیق 68/0 بود که نشان دهنده یک کاهش 32 درصدی در تصادفات است. ارزیابی معناداری آماری این کاهش نیز نشان داد که کاهش 32 درصدی تصادفات در سطح اطمینان 90 درصد معنادار است. در نتیجه می توان با اطمینان 90 درصد انتظار کاهش حدود 30 درصدی تصادفات پس از احداث میدان در تقاطع با کنترل توقف را داشت.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Evaluation of Safety Effect of Roundabout on Intersection Crashes Reduction

نویسندگان [English]

  • Mohammad Koohi 1
  • Shahin Shabaani 2
1 M.Sc., Grad., Department of Civil Engineering, Payam Noor University (PNU), Tehran, Iran.
2 Department of Civil Engineering‌, Payam Noor University (PNU), Tehran, Iran.
چکیده [English]

Determining the numerical value of the safety effectiveness of countermeasures or the Crash Modification factor (CMF) is one of the issues that has received considerable attention in recent years in the world. In this regard, several studies have been carried out to determine the CMF for converting intersection to roundabout in different countries. The results of these studies have led to a reduction of about 35 to 70 percent of crashes at the intersections. Since there is no serious study regarding determining CMF of constructing a roundabout and the percentage of crash reduction due to this countermeasure in Iran, the researchers are seeking to determine the CMF and reduction percentage of the crashes due to this measure in Iran. For this purpose, Salman Farsi roundabout of Ilam city was evaluated. AADT rates were obtained from the available traffic counts and crash data from the police. For determining CMF, empirical Bayes method was considered. The reason for using empirical Bayes method is its high efficiency in removing the phenomenon of regression to mean and other time-alteration factors and the high precision of this method is due to the use of SPF in order to reasonably estimate the frequency of crashes in the period prior to countermeasure. During studying, a SPF from AASHTO 2010 was used. Using this tool and predicting crashes before and after the construction of the roundabout, as well as calculating the frequency of expected crashes before and after it, the effectiveness of safety was calculated. The results for crash frequency is as crash CMF and crash frequency reduction percentage indicates a CMF of 0.68, implying a 32 percent reduction in crash. The statistical significance evaluation of this reduction shows that the 32 percent reduction of crashes after constructing roundabout is significant at 90 percent confidence level.

کلیدواژه‌ها [English]

  • Evaluation of Safety Effect
  • Roundabout
  • Crashes Reduction
  • Empirical Bayes
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