基于双Gamma分布的高速合流区通行能力分析

Capacity of Expressway's Merge Area Based on Double Gamma Pdf

高速公路合流区为主线与匝道交汇处,是引起高速公路交通问题的主要瓶颈区域。为研究高速公路合流区处的通行能力,分析出通行能力的主要影响因素为车头时距,并将双Gamma分布概率密度函数与主线外侧车头时距相联系,得出其拟合性较强的概率曲线;利用积分的思想对合流区汇入量进行了模型确定,并以实测数据对其拟合效果进行验证,得到其合流区的最大汇入量,与实际汇入量进行对比,认为计算结果可信度高。

Expressway＇s merge area which is the main part causing traffic accident in freeway is located in the interchange of the mainline and the ramp. In order to study the expressway＇s merge area＇s traffic capacity, this paper makes reference to related research results of scholars at home and abroad. Based on these results this paper establishes the contact with the double Gamma probability density function （Double GamPDF） and the headway of outside lane. In this way it can achieves a probability curve. Using the measured data verify the fitting effect can conclude the curve is strongly fitting. Double GamPDF is introduced to integral and the model of merging area＇s import volume can be determined by using integration method. The data of the numbers of vehicles and the headway both in main lane and ramp in Xi＇an ring expressway are obtained through the survey. The survey data is used to compute the max number of import volume. Compared with the measured import volume can prove that the calculation result is reliable and has high suitability.