Characterization of vehicle time headway in clear and rainy weather
Date
2018-12-14
Authors
Tangestanipour, Atousa
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Adverse weather has a direct effect on traffic congestion, capacity, and road safety. Rain
can influence traffic flow and headway. Thus, it is important to study the impact of weather
conditions on traffic. In this thesis, headway data from a north-south highway in Tehran is
categorized according to weather conditions and traffic flow. A statistical analysis of this
data is presented which show that the mean time headway increases in rainy weather and
the traffic flow rate is lower. The probability density functions fit to the headway data and
these distributions are then evaluated using the Chi-Squared (C-S) and Kolmogorov-
Smirnov (K-S) tests to determine which is the most suitable. To generalize results for
different traffic flow rates, another highway was selected for data collection. The results obtained show that the Burr distribution is the best to model the headway data in clear and
rainy weather with a higher traffic flow. Moreover, the generalized extreme value distribution is the best to model the headway data in clear and rainy weather with a lower
traffic flow. This justifies the use of different time headway distributions in rainy and clear
weather conditions and different traffic flow rates for traffic modeling.
Description
Keywords
Vehicle Headway Time, Burr distribution, Generalized extreme value distribution, Statistical model