基于交通冲突模型的信号交叉口渠化岛设置方法

为了优化信号交叉口渠化岛, 提出了一种基于交通冲突模型的信号交叉口渠化岛设置方法; 提取了昆明市20个信号交叉口交通冲突数据、交通流数据、交通控制方式数据和几何设计数据, 采用贝叶斯方法, 构建了贝叶斯固定参数交通冲突模型和贝叶斯随机参数交通冲突模型, 分析了模型的拟合优度和显著影响因素; 基于随机参数交通冲突模型, 确定了期望交通冲突数计算公式; 绘制了信号交叉口渠化岛设置标准曲线, 给出了信号交叉口渠化岛类型选择流程。分析结果表明: 随机参数交通冲突模型比固定参数交通冲突模型拟合结果更好; 交通量(直行交通量和右转交通量)、渠化岛类型与右转设计要素(右转让行标志和右转半径) 变量系数服从正态分布; 每增加1%的直行交通量, 交通冲突增加0.56%;每增加1%的右转交通量, 交通冲突增加0.53%;4种类型渠化岛的设置可以使交通冲突分别降低12.75%、23.37%、16.18%、33.64%;右转让行标志可使交通冲突降低15.03%;右转半径增加1%, 直右交通冲突降低1.72%。可见, 基于交通冲突模型的渠化岛设置方法是可行的。

Design approach of channelized island based on traffic conflict models at signalized intersection

In order to optimize the channelized island design at signalized intersection, a design approach of channelized island based on traffic conflict models was proposed. Traffic conflict data, traffic flow data, traffic control data, and geometric design data were collected at twenty signalized intersections in Kunming. Adopting Bayesian method, Bayesian fix parameter traffic conflict model and Bayesian random parameter traffic conflict model were constructed. The fitting goodnesses and significant influencing factors of the models were analyzed. Based on the random parameter traffic conflict model, the formula of calculating the expected number of traffic conflicts was determined. The design standard curves of channelized islands at signalized intersections were drawn, and the type selection procedure of channelized islands was proposed. Analysis result shows that the random parameter traffic conflict model yields better fitting result than the fixed parameter model. The variable coefficients of traffic volumes (crossing through traffic volume and right-turn traffic volume), channelized island types, and right-turn design elements (right-turn yielding sign and right-turn radius) obey normal distributions. When the crossing through traffic volume increases by 1%, the traffic conflict frequency increases by 0.56%. When the right-turn traffic volume increases by 1%, the traffic conflict frequency increases by 0.53%. The four types of channelized islands can reduce the traffic conflict frequency by 12.75%, 23.37%, 16.18% and 33.64%, respectively. The right-turn yielding sign can reduce the traffic conflict by 15.03%. When the right-turn radius increases by 1%, the right-turn traffic conflict frequency reduces by 1.72%. The research conclusion indicates that the design approach of channelized islands based on the traffic conflict models is feasible.