信号交叉口专用双左转车道通行能力

Capacity of exclusive dual left-turn lanes at signalized intersection

在北京市6个信号交叉口双左转车道交通流数据调查的基础上,应用数理统计学方法对信号交叉口双左转车道饱和车头时距和饱和流率以及影响因素进行了研究。通过比较算术平均值、截尾均值和中值计算结果,提出应用截尾均值法计算饱和车头时距与饱和流率。研究了饱和流率与车道宽度、转弯半径的关系,应用回归方法给出了饱和流率与转弯半径关系模型,并对内、外侧车道饱和流率与单一左转车道饱和流率进行了比较。研究结果表明:内侧车道饱和车头时距为2.14～2.60s,外侧车道饱和车头时距为2.08～2.37s,平均饱和流率为1600pcu.(h.lane)-1;双左转车道饱和流率为单一左转车道饱和流率的1.80～2.05倍。

Based on the survey data of six signalized intersections with dual left-turn lanes in Beijing,the saturation time-headways,saturation flow rates and their influencing factors of dual left-turn lanes at signalized intersections were studied by using statistical methods.By comparing with arithmetic mean value and median value,the trimmed mean value method was used to calculate the saturation time-headway and saturation flow rate.The effects of lane width and turning radius on the saturation flow rate were studied,and the regression model of saturation flow rate with turning radius was suggested.The saturation flow rates of inside lane,outside lane and single left-turn lane were compared.Analysis result shows that the saturation time-headway of inside lane is 2.14~2.60 s,the saturation time-headway of outside lane is 2.08~2.37 s,and the average saturation flow rate is 1 600 pcu·（h·lane）-1.The ratio of sum saturation flow rate of inside lane and outside lane to that of single left-turn lane is 1.80~2.05.6 tabs,1 fig,11 refs.