Afshin Shariat Mohaymany

تحلیل وضعیت ترافیکی و پیشنهاد روش‌های مدیریت جریان ترافیک نقش اساسی در ارزیابی عملکرد بسیاری از سیستم‌های حمل‌ونقلی ایفا می‌کند. در بین روش‌های جمع‌آوری داده‌های ترافیکی، رویکردهای مبتنی‌بر فنّاوری‌های نوین که امکان گرد‌آوری حجم بسیاری از داده‌های پویای زمانی‌ـ مکانی را فراهم می‌آورند و استخراج روندها و الگوها را تسهیل می‌کنند اهمیت بسیاری دارند. در این پژوهش، تهران به‌منزلة پایتخت ایران، با ویژگی‌های اقتصادی و اجتماعی خاصی که دارد و تنوع سفرها که به وضعیت ترافیکی متغیر منجر می‌شود، مطالعه شده است. داده‌های حاصل از پردازش رقومی تصاویر ترافیکی به‌دست‌آمده از سرویس نقشة گوگل در بازة زمانی پیوستة یک‌ماهه‌ای (هفدهم فروردین تا هفدهم اردیبهشت 1398)، نخستین بار به‌منظور ارزیابی روند تغییرات میانگین ازدحام ترافیکی در سطح نواحی منطقة مطالعاتی، به‌کار رفته است. پس از استخراج داده‌های اولیه و با توجه به تغییر الگوی سفرها و در نتیجه، میزان ازدحام ترافیکی، شاخص ازدحام ترافیکی (CI) به‌تفکیک در روزهای کاری و غیرکاری، محاسبه شد و به مرکز نواحی 117‌گانة شهر تهران اختصاص یافت. با استفاده از تحلیل‌های توصیفی روی...

Existing travel time reliability measures fail to accommodate scheduling preferences of travelers and cannot distinguish between the variability associated with early and late arrivals. This study introduces two new travel time reliability measures based on concepts from behavioral economics. The first proposed measure is an indicator of the width of travel time distribution. It considers scheduling preferences of travelers and can distinguish between early arrival and late arrival. The second measure determines the skewness of travel time distribution. To estimate the proposed measures, travel time is modeled by mixture models and closed-form expressions are derived for the expected values of early and late arrivals. In addition, real travel time data from a freeway segment is used to compare the proposed measures with the existing travel time reliability measures. The results suggest that, although there exist significant correlations between travel time reliability measures, travelers’ preferences have considerable effects on the travel time reliability as perceived by them. Furthermore, four measures are developed based on the notions of early and late arrivals to assess the on-time performance (schedule adherence) of transit vehicles at stop level. The results of this study show that the four measures can serve as complementary to the existing on-time performance indices.

The current study aims to investigate the aberrant driving behaviour and risk involvement of Iranian taxi drivers. The sample comprised 405 Iranian taxi drivers, who were recruited with a cross-sectional design, using a self-completion questionnaire survey during October and November 2016. We contribute to the literature by understanding how and to what extent the socioeconomic, demographic, driving, and aberrant driving behaviours influence risk involvement (accident involvement and traffic tickets). The validated 27-item Driver Behaviour Questionnaire (DBQ) was applied to measure aberrant driving behaviour. The results from valid observations (n = 381) explored a four-factor solution (including errors, ordinary violations, lapses, and aggressive violations) of the DBQ. The results also showed that being a single driver, having a high annual driving mileage, and a high number of daily taxi trips were positively associated with accident involvement. Furthermore, there was a positive correlation between the more ordinary violations and aggressive violations and accident involvement. Establishing better training and qualification mechanisms for taxi drivers could be considered by traffic safety experts in order to reduce ordinary and aggressive violations.