交通信息与安全Issue(1)：57-63,7.DOI:10.3963/j.issn 1674-4861.2016.01.001
城市道路隧道入口车头时距的幂律分布研究∗
A Study of Power-law Distribution of Headways at Urban Tunnel Entrance
摘要
Abstract
Headway is one of the most important parameters in traffic flow and random process.In order to study the statistical characteristics of traffic flow at tunnel entrance,this study investigates headway data on different lanes and different periods in Guanzhou tunnel and CBD tunnel in Guangzhou.The results show that the random process of vehicle headway deviates from the negative exponential distribution,and presents non-Poisson characteristics.A new power-law distribution function is therefore proposed to fit the headway distribution.Furthermore,the unknown parameters for the proposed power-law distribution are estimated by maximum likelihood estimation and genetic algorithm.The goodness-of-fit of model is verified through a Chi-square test against 9 sets of observed data.The results show that the empirical head-way distributions present the feature that the headways firstly increase and then decrease.The results also illustrate that the exponential distribution does not fit the observed data and is rejected by the Chi-square test.The non-Poisson charac-teristic of headway distribution is clear.On the other hand,the power-law distribution fits the observed datasets well with the fact that 8 out of 9 data sets passed the Chi-square test.In conclusion,the power-law distribution can fit the headway distribution well,especially when non-Poisson characteristics are dominant.The mechanism and dynamic effect behind the non-Poisson characteristics requires further study.关键词
城市交通/道路隧道入口/车头时距/非泊松特性/幂律分布/参数估计/拟合优度检验Key words
urban traffic/urban tunnel entrance/time headway/non-Poisson/power-law distribution/parameter estimation/goodness-of-fit test分类
交通工程引用本文复制引用
陈新宇,臧晓冬,赵斌..城市道路隧道入口车头时距的幂律分布研究∗[J].交通信息与安全,2016,(1):57-63,7.基金项目
国家级大学生创新训练项目(201411078010,201511078013)、广东省大学生创新训练项目(201411078038)资助 （201411078010,201511078013）
