高速条件下隧道出入口行驶速度特性

Characteristics of driving speed at tunnel entrance and exit at high speed

为明确山区隧道出入口区段的车辆运行特性和驾驶行为,揭示隧道洞口交通事故的发生机制,在高速公路和城市快速路各选择3座隧道,采集了小客车和货车在隧道出入口区段的断面速度,高速公路单个断面观测样本大于500 veh,快速路隧道单个断面样本大于1100 veh,基于断面数据分析了车辆行驶速度的变化规律和影响因素,并建立了运行速度预测模型。分析结果表明:驾驶人临近隧道洞口时会减速,小客车速度降幅为12~21 km·h^(-1),货车速度降幅为2~10 km·h^(-1),货车速度降幅低于小客车;洞口位置小客车运行速度大于80 km·h^(-1),货车运行速度大于70 km·h^(-1);高速公路隧道出入口段的车速范围为75~110 km·h^(-1),快速路隧道出入口段的车速范围为60~88 km·h^(-1),高速公路隧道出入口段的车速普遍高于城市快速路隧道;驾驶人进入隧道洞内适应环境之后会加速行驶,驶出隧道时有加速行为,但当隧道出口前方有小半径弯道和互通立交时,驾驶人会减速以适应前方的道路条件;隧道入口前100 m至洞口范围内的车辆减速度最大,货车减速度范围为0.23~0.58 m·s^(-2),小客车减速度范围为0.47~0.70 m·s^(-2);同一断面的速度观测值存在较强的离散性,表明车辆之间存在明显的纵向干涉,容易发生追尾事故。

In order to clarify the operating characteristics and driving behavior at the entrance and exit of mountain tunnels and reveal the mechanism of traffic accidents at tunnel portals,three tunnels on expressways and urban express roads were selected,respectively.The spot speeds of passenger cars and trucks at the entrances and exits of these tunnels were collected.The observation sample size for a single section on the expressway is more than 500,for the urban fast road tunnel,it is more than 1100.The variation rules and influencing factors of vehicle speed were analyzed based on the section data,and the predictive model of vehicle speed was developed.Analysis results show that drivers will slow down vehicle speed when approaching the tunnel portal.The speeds of passenger cars and trucks decrease by 12-21 and 2-10 km·h^(-1),respectively.The speed decrease of truck is lower than that of passenger car.Near the tunnel portal,the speeds of passenger cars and trucks are more than 80 and 70 km·h^(-1),respectively.The speed range of the expressway tunnel entrance and exit section is 75-110 km·h^(-1),for the entrance section of the fast road tunnel,it is 60-88 km·h^(-1).The speed at entrance or exit of the expressway tunnel is generally higher than that of the urban fast road tunnel.Drivers speed up after acclimatizing in the tunnel and accelerate when they depart the tunnel.However,they slow down when there is a sharp curve and interchange in front of the tunnel exit.The deceleration of vehicle within 100 m in front of the tunnel entrance is the largest.The decelerations of trucks and passenger cars are 0.23-0.58 and 0.47-0.70 m·s^(-2),respectively.The speed data measured at the same section have strong discreteness,indicating an obvious longitudinal interference among various vehicles,which is easy to cause rear-end collision.5 tabs,8 figs,30 refs.