高速公路施工区层级限速问题研究

Research on Level Speed-limit Problem in Expressway Construction Area

为确定高速公路施工区层级限速值,基于VISSIM仿真软件建立了双向四车道高速公路施工区多种限速仿真方案,在不同交通量、固定的大车混入率以及二并一的道路封闭形式条件下,分别对施工控制区中的警告区和上游过渡区的限速降幅值与安全性关系进行了对比研究。结果表明:2个控制区在相同交通量和限速方案条件下,车速降幅值与冲突率的关系不同;同一控制区内,相同交通量、不同限速方案条件下,车速降幅值与冲突率关系存在相似性,且每个交通量条件下都分别存在冲突率较低的车速降幅值,即控制区限速降幅的安全范围;不同控制区内,交通量条件不同,车速降幅值的安全范围亦不同;在警告区和上游过渡区内设定限速值时,应根据交通量合理选择。

To determine level speed-limit in expressway construction area, various speed-limit simulation schemes were established in two-way four lanes＇ expressway construction area by VISSIM. Under different traffic volumes, fixed mixing rate and two lanes with one closed, relationships between the drop rate of speed-limit and security in the warning zone and the upper transition zone were compared. The results indicate that the relationships of the drop rate of speed-limit and the conflict rate in the two control areas are different under the condition of the same traffic volume and speed-limit scheme. For one control area with the same traffic volume and different speed-limit schemes, the relationships between the drop rate of speed and conflict rate were found to be similar and the drop rate of speed-limit with the low conflict rate under each traffic volume had been found, which was defined as the reasonable drop rate of speed-limit in control area. Reasonable scopes of drop rate of speed-limit are different in various control areas with different traffic volumes. In the setting of speed-limit in warning area and upper transition area, reasonable drop rates should be set according to the traffic volume.