中文摘要：

鉴于Pacey提出的车队密度离散模型中车速为从负无穷到正无穷上的正态分布这一假设与实际车速分布情况明显不符，基于实地收集数据，从交通流密度的角度，假设车速服从在最小速度至最大速度之间的截断对数正态分布，由此分析了上游交叉口的排队车辆在绿灯放行后往下游道路行驶过程中的离散特性，利用分段函数方式构造了车队在时空坐标上的交通流密度函数的计算公式．针对信号协调控制应用，提出了在某一时刻公交车队头部驶过和尾部未驶过下游断面的车辆数计算公式，推导了下游交叉口断面处的流量分布模式，结合实测数据分析，验证了模型的有效性．

英文摘要：

As Pacey＇s platoon dispersion model assumes the speed following normal distribution spreading from negative to positive infinity, which doesn＇t properly reflect the real observations, based on field collected data, from the density view, by assuming the speed following truncated lognormal distribution ranging from minimum speed to maximum speed, the platoon dispersion characteristics as it moves down along the road was investigated, and a piecewise density function was developed. Based on the density function, the expected number of cars at the front of the platoon past and the expected number of cars at the rear of the platoon not past a downstream point were derived function at downstream intersection was developed. Case study and numerical ana validity of the proposed model. Besides, the flow sis confirmed the