基于航拍数据的高速公路出口环圈匝道行车安全性评价方法

Aerial photography data-based method for evaluating traffic safety of highway exit loop ramps

为准确评估高速公路环圈匝道不同交通状况下碰撞护栏和追尾的风险,改善出口环圈匝道行车安全不足现状,提出一种基于航拍数据的行车风险评估方法。首先,通过分析3个实际案例的车辆速度和轨迹数据,总结高速公路互通式立交出口环圈匝道的车辆行驶特征,并定义2种主要的事故类型(车辆进入匝道后与左侧护栏相撞、由于跟驰状态导致的追尾)。其次,介绍如何计算安全评估指标(横向距离和碰撞时间),并根据出口环圈匝道特点选择合适的评估阈值,建立行车安全性评估方法。最后,通过实际案例的分析,验证该方法的有效性。研究结果表明:车辆在匝道内的速度和轨迹控制呈现一致性,车辆需要约135 m的距离从变速到稳定;为避免与左侧护栏相撞,车辆在匝道内会有向右偏移的趋势,偏移长度与初始车速相关;在减速车道上,车辆几乎没有撞击护栏的风险,但在跟驰状态下,前车进入匝道可能导致追尾事故;车速过快可能导致在匝道入口处与左侧护栏相撞;所提出方法与历史事故数据的预测结果相符。研究提供了一种新的出口环圈匝道行车安全性分析方法,将行车特征与安全性分析量化,可为立交出口的管理和设计提供理论支持。

In order to accurately assess the collision guardrail and tailgating risk under different traffic conditions on highway loop ramps,and to improve the current situation of insufficient traffic safety on exit loop ramps,a driving risk assessment method based on aerial data was proposed.Firstly,by analyzing the speed and trajectory data of three actual cases,the vehicle travel characteristics of highway interchange exit loop ramps were summarized and two main accident types were defined,vehicle collision with the left guardrail after entering the ramp and tailgating due to the following driving.Then,the calculation methods of safety assessment indexes lateral distance and time to collision were introduced,and the traveling safety assessment method was established by selecting appropriate assessment thresholds according to the characteristics of the exit loop ramp.Finally,the effectiveness of this method was verified through the analysis of a real case.The results show that the speed and trajectory control of the vehicle in the on-ramp show consistency,and the vehicle needs about 135mto go from speed change to stabilization.In order to avoid collision with the left guardrail,the vehicle tends to shift to the right in the on-ramp,and the length of the shift is correlated with the initial speed.In the decelerating lane,there is almost no risk that the vehicle will hit the guardrail,but in the following condition,the front vehicle enters into the on-ramp which may lead to tailgate accidents.Excessive vehicle speed may lead to collision with the left guardrail at the ramp entrance.The proposed method is consistent with the prediction results from historical accident data.This study provides a new method for analyzing the driving safety of exit loop ramps,which quantifies the driving characteristics and safety analysis,and can provides theoretical support for the management and design of interchange exits.4tabs,11figs,37refs.