环形立交匝道汽车横向加速度特征实车测试研究

环形匝道是一类常用的互通立交匝道形式,同时也是行驶条件困难、事故高发的弯坡组合路段。为明确环形匝道的横向加速度特征,在重庆辖域内选择3座完全苜蓿叶形互通立交和1座部分苜蓿叶形立交作为研究对象,开展实车驾驶试验,采集自然驾驶条件下的汽车横向加速度连续数据,明确环形匝道的横向加速度幅值水平、变化趋势和模式。结果表明:不同驾驶人的横向加速度曲线幅值和外观形态存在显著差异,但可以对其进行归类;3座完全苜蓿叶形互通立交环形匝道的横向舒适性水平一般,1座部分苜蓿叶形立交环形匝道的横向舒适性水平较差(不舒适);环形匝道的横向加速度变化模式可以分为7种,其中三阶段模式为5种,两阶段和四阶段各1种,占比最大的模式特征是横向加速度值在匝道中间阶段仍是单调上升的;增加缓和曲线长度可以降低环形匝道驶入/驶出阶段的横向加速度增长率。

Field investigation of passenger car lateral acceleration on loop ramps of interchanges

Loop ramp is a kind of commonly used interchange ramp form, at the same time it is also a accident prone section with difficult driving condition because it is a curved- slope combination section. In order to clarify the lateral acceleration characteristics on loop ramp, three complete clover leaf interchanges and one partial clover leaf interchange in Chongqing jurisdiction were selected as the research object, and the real vehicle driving experiment carried out, The continuous lateral acceleration of running cars under natural driving conditions were collected, and the amplitude level, changing trend and patterns of lateral acceleration for loop ramp are defined, and the main conclusions are as follows: There are significant differences in the amplitude and appearance morphology of lateral acceleration curves of different drivers, but they can be classified. Ride comfort level in lateral direction of loop ramps of three completely clover leaf interchanges are general, and comfort level for loop ramp of one partial clover leaf-shaped interchange is poor (uncomfortable). The patterns of lateral acceleration for loop ramps can be divided into seven kinds, five kinds of which are the three-stage patterns, one is two-stage and the other one pattern is four stage. The pattern with largest proportion behaves: the value of lateral acceleration is still monotonically rising in the middle stage of the loop ramp. Increasing the length of spiral curve can reduce growth rate of lateral acceleration when drivers entering/departing the loop ramps.