Abstract: The influential extent of weaving area is an important factor in the research of the cloverleaf interchanges capacity. This paper has analyzed the limitation of using the dividing principle in the diverging area, the merging area and the weaving area from HCM2000 on cloverleaf interchanges. Based on the data surveyed on the cloverleaf interchanges in Guangzhou, according to the theoretic analysis and the statistic theory, researching the time headway distribution characteristics in the upstream and the downstream of A type weaving area(Weaving vehicles in both directions must make one lane change to successfully complete a weaving maneuver.) and C type weaving area (Weaving vehicles in one direction may complete a weaving maneuver without making a lane change, whereas other vehicles in the weaving segment must make two or more lane changes to successfully complete a weaving maneuver), the researching results have verified that the weaving area influences the traffic flow characteristics of its upstream and its downstream, and the time headway distribution in upstream and downstream of A type weaving area and C type weaving area of cloverleaf interchanges accords with the three parameters Weibull distribution, then according to the variational rule of shape parameter in Weibull model with the distance, the paper confirms the influential extent of A type weaving area and C type weaving area to its upstream and its downstream.

Key words: traffic engineering, influential extent, statistic theory, cloverleaf interchanges, weaving area

摘要： 快速路苜蓿叶互通立交通行能力研究中,交织区影响范围是其中重要的参数. 本文分析了《美国通行能力手册》(HCM2000)对分合流区和交织区的划分原则应用在苜蓿叶互通立交上的局限性. 通过采集广州市快速路苜蓿叶互通立交上的数据，应用理论分析和数理统计的方法，研究了苜蓿叶互通立交A型交织区（交织车辆至少需要1次车道变换）和C型交织区（一股车流不用车道变换，另一股需要两次或两次以上车道变换）上下游的车头时距分布特性. 研究结果表明，交织区对上下游的交通流有影响，A型交织和C型交织上下游的车头时距分布符合三参数韦布尔分布. 然后根据韦布尔分布中形状参数随距离的变化规律，确定了苜蓿叶互通立交A型交织和C型交织对上下游的影响范围.

关键词: 交通工程, 影响范围, 数理统计, 苜蓿叶互通立交, 交织区