Abstract    The desired gap headway of drivers, while close following, represents the main parameter in determining the following distance between vehicles. This paper uses the raw individual vehicles data taken from loop detectors for millions of vehicles used M25 and M42 in order to estimate the gap headway distributions between successive pairs of vehicles. The data used in this paper were filtered so as to focus on the cases of close following behavior only and more than quarter million pairs of close following cases is used to presents the results. Such huge sample size taken from loop detectors will increase the results reliability as previous research used limited sample size. The results presented the cumulative distribution of drivers’ gap headway and suggested that the mean gap headway of drivers is about 1.1 s with standard deviation of 0.42 s. The lane choice found to be significantly influencing the desired gap headway for speed higher than 70km/h only. The effect of the follower vehicle type of the desired gap headway was also examined and the results suggested that such effect is insignificant. The findings of this paper are suggested to be used as inputs for traffic micro-simulation models.

Keywords    Gap Headway Distribution; Drivers’ Reaction Time; Close Followin; Microsimulation; Vehicle Types; Following Distance

چکیده    گشتاور مورد نظر رانندکان در حالی که نزدیک بودن، نشان دهنده پارامتر اصلی در تعیین فاصله بین وسایل نقلیه است. این مقاله از داده های خودروهای خام فردی گرفته شده از آشکارساز حلقه برای میلیون ها خودرو استفاده شده از M25 و M42 به منظور تخمین توزیع پیشرفت شکاف بین جفت های متوالی وسایل نقلیه استفاده می کند. داده های مورد استفاده در این مقاله فیلتر شده اند تا تمرکز بر موارد رفتاری نزدیک باشد و بیش از یک چهارم میلیون جفت موارد زیر برای ارائه نتایج استفاده می شود. اندازه نمونه ای بزرگ از آشکارسازهای حلقه به عنوان تحقیق قبلی استفاده از اندازه نمونه محدود افزایش اعتبار نتایج را افزایش می دهد. نتایج نشان داد که توزیع تجمعی ریزپردازنده رانندگان، نشان می دهد که متوسط رانندگی شکاف رانندگان حدود 1/1 ثانیه با انحراف معیار 42/0 ثانیه است. انتخاب لاین نشان داد که به طور قابل توجهی تحت تاثیر سرعت پیشرفت مورد نظر برای سرعت بیش از 70 کیلومتر در ساعت تنها است. اثر نوع وسیله نقلیه دنباله ای از مسیر پیشرفت مورد نظر نیز مورد بررسی قرار گرفت و نتایج نشان داد که چنین اثر ناچیز است. یافته های این مقاله پیشنهاد می شود که به عنوان ورودی برای مدل های شبیه سازی ترافیک ترافیکی استفاده شود.

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