摘要
本文对快速道路服务水平评价的重要指标——自由流车速进行了深入研究。根据上海市城市快速路交通信息采集系统所积累的大量数据,取在单位时间内通过检测断面的车辆数为1,占有率<3％的情况为近似的车辆自由流行驶状态,分析该状态下断面或车道的车速情况。通过数据统计分析发现:车辆在自由流行驶状态下,速度在检测断面和车道上的分布形式均满足正态分布。利用正态分布的特征值,本文定义了基于实测数据和统计学方法的自由流车速。
This research is based on the urban expressway evaluation system established on the concept of equivalent capacity and it investigates into a critical index-free-flow velocity. Based on the massive data collected by the urban expressway data collection system, this research defined the status that only one vehicle crossed a specific transect and occupy less than 3 percent in a given time as free flow and analyzed the velocity of the given transect or lane. Through statistics and analysis, it is found that when in the status of free flow, vehicles＇ velocities on the transect or lane fit into normal distribution. Then, we give a new definition to free-flow velocity based on massive data and statistics.
出处
《交通与运输》
2006年第B12期28-31,共4页
Traffic & Transportation
