环形交叉口储备通行能力计算

Study of Reserve Capacity of Roundabouts

在介绍环形交叉口入口通行能力、交织段通行能力和总通行能力等计算方法的基础上,给出了环形交叉口流量流向矩阵形式并以此来表达冲突流量,对于入口通行能力的线性回归模型,以各入口流量之和达到最大值为目标及各入口车流饱和度均满足一定服务水平为约束,假设交叉口各入口转向比例不变并当实际流量增加时,首先在环形交叉口某一瓶颈入口处达到饱和,此时环形交叉口各入口流量之和即为储备通行能力.论文给出了储备通行能力的推导过程并以英国Kimber公式、瑞士Bovy等人的公式为例,针对大连市数码广场环形交叉口的实际调查数据,用两种方法计算出该交叉口的储备通行能力.结论说明:该方法对于入口通行能力为线性回归模型的环形交叉口储备通行能力的计算均适用,并可由此找出环形交叉口的瓶颈入口.

Some calculation methods of roundabouts entry capacity,waving section capacity and full capacity were introduced,and a target of archiving the maximum sum of all entries flow rate and a constraint which all entry saturations meet certain level of service conditions is proposed based on linear regression model for roundabout entry capacity.After acquired the traffic flow data of roundabouts,the greatest possible flow rate named as the reserve capacity can be derived on the assumption that the flow rate of each direction change with the same ratio and that running bottleneck is existed in the roundaboutk.Two methods using Kimber formula and Bovy formula are given to calculate the roundabout reserve capacity based on the data of four-entry roundabout.The result illustrates that the model can be applied for the calculation of roundabouts reserve capacity when lineal regress model is used to calculate entry capacity.The bottleneck entry can be found also.