中文摘要：

为了得到城市道路间断流的速度-密度关系，定义了宏观速度和密度参数，利用VISSIM仿真获取基础数据并进行统计分析，进而引入4参数Logit模型完成数据拟合，建立了速度-密度的4参数Logit模型。其次，分析了交通组成、道路几何形式和信号控制参数对模型参数的影响，完成了模型参数与影响因素之间的多元回归拟合，建立了适用于不同条件下的间断流速度-密度模型。通过实际数据验证，得到的一般4参数Log-it模型的拟合优度为0．7左右，能够较为准确地描述间断流速度-密度关系。

英文摘要：

In order to obtain the relation between speed and density of discontinuous traffic flow for urban street, first, the macroscopic speed and density parameters are defined, and the fundamental data are obtained and the statistical analysis is conducted by VISSIM simulation. Four-parameter Logit model is used to fit the obtained data, and a 4-parameter Logit model for speed-density relation is established. Second, the effects of traffic composition, road geometric configuration and signal control parameters on the model parameters are explored, the multiple regression fitting between model parameters and influencing factors is conducted, the discontinuous flow speed-density model which can be used under various conditions is proposed. Finally, practical data are used to verify the proposed general 4-parameter logit model, and the fitting goodness is around O. 7, which implies the model can describe the discontinuous flow speed-density relation precisely.