高速公路直线段边缘率控速标线周期长度设计模型

Cycle Length Design Model of Edge Rate Speed Control Line on Highway Straight Sections

为了探索边缘率控速标线周期长度对降速行为的影响现象,构建周期长度设计模型,在4条高速公路直线段上重复开展了边缘率控速标线周期长度分别为16,8,4,2,1m的控制性试验。采集车速特征数据,依据边缘率定义计算了单个车辆所对应的时间频率,建立了时间频率与加速度之间的关系,在此基础上,考虑事故率、事故强度与车速指标的关系,结合路段车速分布特征建立边缘率控速标线周期长度设计模型,并给出对应算法。研究结果表明:时间频率是周期长度影响减速效果的内在因素,当时间频率处于[10,18]Hz时,驾驶人一致采取制动行为,降速幅度随时间频率的增大而增大,当车辆对应的时间频率等于18Hz时,驾驶人一致减速效果最大,且4个试验地点的时间频率与加速度呈显著且稳定的线性相关关系;当时间频率处于[1,10)Hz时,各时间频率所对应的加速度值均小于0;当时间频率大于18Hz时,各时间频率所对应的加速度均值小于0,但其减速幅度显著小于时间频率为18Hz时的,控速效果弱。鉴于此,以车速标准差最小以及将最高车速控制在安全车速以内为目标,以时间频率上限值、时间频率与加速度之间的关系、铺设终点与起点车速关系、边缘率控速标线周期长度最大值为约束构建了边缘率控速标线周期长度设计模型,该模型可用于边缘率控速标线周期长度的优化,提高其控速效果。

To explore the influence of the edge rate speed control line cycle length on the speed control behavior, and to build a cycle length design model, experiments were repeatedly carried out on the straight sections of four highways by controlling the edge rate speed control line cycle length at 16, 8, 4, 2, 1 m. The speed data were collected, the temporal frequency corresponding to every single vehicle was calculated based on the definition of the edge rate, and the relationship between the temporal frequency and acceleration was determined. On this basis, considering the relationship among the accident rate, accident intensity, and vehicle speed index, and combining the characteristics of the road speed distribution, the cycle length design model and the corresponding algorithm of the edge rate speed control line were established. It was found that the temporal frequency is an internal factor of the cycle length affecting the speed reduction. When the temporal frequency was between 10-18 Hz, the drivers consistently braked, and the reduction in speed increased over the temporal frequency, whereas when the temporal frequency was equal to 18 Hz, the most consistent deceleration effect occurred, and significant and stable linear relationships between the temporal frequency and acceleration were shown during the four test sites. When the temporal frequency was between 1-10 Hz, the acceleration corresponding to every temporal frequency was less than zero. When the temporal frequency was greater than 18 Hz, the mean acceleration corresponding to every temporal frequency was less than zero- however, the reduction in speed was significantly less than its counterpart when the temporal frequency was 18 Hz, and the control speed effect was inferior. Accordingly, with the aim of minimizing the standard deviation in speed and keeping the top speed at less than the safe speed, and considering the upper limit of the temporal frequency, the relationship between the temporal frequency and acceleration, the relationship between the end point and the starting speed, and the maximum length of the edge rate speed control line as constraints, a cycle length design model of the edge rate speed control line was established. This model can be used to optimize the cycle length of the edge rate speed control line and improve the speed control effect.