双车道二级公路纵坡段车辆运行速度预测模型

在分析双车道二级公路不同坡度、坡长纵坡的大量运行速度实测数据的基础上,得出车辆运行规律。通过研究纵断面要素(坡度、坡长)与车辆运行速度的关系,确定自变量参数后,利用SPSS软件进行回归分析,分别建立了小车上坡、大车上坡在坡中和坡顶以及小车下坡、大车下坡在坡中和坡底的运行速度预测模型,并对模型进行了检验。结果表明:车辆运行速度随坡度增加而减小,其变化的幅度受坡长影响;预测模型分别通过了回归等式的显著性检验、回归参数的显著性检验和回归等式应用准确度的检验,所有模型的相对预测误差平均值均小于5%,建立的回归模型精度满足要求。

Operating Speed Prediction Model on Gradient Section for Two-lane Secondary Highway

On the basis of analyzing the massive measured data of operating speed on two-lane secondary highways for gradient sections with different grades and slope lengths,the operation rules of vehicles were obtained.By studying the relationship between profile elements(grade and slope length) and operating speed of vehicles,authors selected independent variable parameters and used SPSS software for regression analysis,then set up the operating speed prediction models on the middle and top of the upgrade sections and on the middle and the base of the downgrade sections for a car and a truck respectively,the models were also verified.Results show that the speed of vehicle decreases with increasing of grade;the rate of speed change is affected by the slope length.Through significant testing of regression equation,regression parameters and application accuracy testing of regression equation,all the means of relative prediction errors of the model are less than 5%.It shows that the regression models are effective.