城市立交上盖交织区交通运行特征分析及优化设计

Characteristic Analysis and Optimization Design of Traffic Operation in Upper-deck Interwoven Area on Urban Interchange

摘要:

为满足城市高速立交市政化过程中土地资源的集约使用，立交上盖改造成为了有效的手段。通过匝道的改建与上盖平台的构筑，上盖结构的内部形成了上盖交织区，该区域耦合了立交交织区和隧道的双重复杂交通特性，不仅存在交织区内车辆频繁变换车道、分流合流等特性，还叠加了隧道环境下视野受限、空间局促等风险，构成了显著的安全隐患。探讨了城市立交上盖交织区交通运行影响因素，并聚焦于上盖交织区出入口实施的实地调研，采集和分析断面速度数据。结果显示，上盖交织区出口附近的断面间速度差、断面速度标准差和断面超速率均较高，表明这些路段交通运行风险较大。此外，结果还显示，设置纵向减速标线能有效降低速度标准差和车辆断面平均速度，减少超速现象，进而降低行车风险，是一项切实可行的交通组织优化策略，对于城市立交上盖交织区的优化设计具有重要应用价值。

关键词:立交上盖;交织区;交通运行特征;优化设计

Abstract:

In order to meet the intensive use of land resources in the municipalizing process of interchange in urban expressways, the upper-deck construction of interchange has become an effective means. Through the reconstruction of ramps and the construction of the upper-deck platform, an upper-deck interwoven area is formed inside the upper-deck structure. This area is coupled with the double complex traffic characteristics of the interchange interwoven area and tunnel, which not only has the characteristics of frequent lane change, diversion and merging of vehicles in interwoven area, but also superimposes the risk factors of limited vision and narrow space in the tunnel environment. As the result, the significant safety hazard is constituted. The influencing factors of traffic operation in the upper-deck interwoven area of urban interchange are discussed. And focusing on the field investigation at the entrance and exit of the upper-deck interwoven area, the velocity data of the section are collected and analyzed. The result shows that the velocity difference between sections, the standard deviation of section velocity and the excess velocity of section are higher near the exit of the upper-deck interwoven area, which indicates that the risk of traffic operation in these road sections is larger. In addition, the result also shows that setting the longitudinal deceleration marks can effectively reduce the standard deviation of speed and the average speed of vehicle section, reduce the over-speed phenomenon, and then reduce the driving risk, which is a feasible optimization strategy of traffic organization with the important application value for the optimization design of the upper-deck interwoven area on urban interchange.

Key words:upper deck of interchange; interwoven area; traffic operation characteristics; optimization design