共查询到19条相似文献,搜索用时 93 毫秒
1.
本文在分析了避险车道现状问题和安全影响因素的基础上,通过货车在雅西高速公路上的制动鼓温度变化实车试验,建立货车在山区高速公路长大下坡路段行驶时的制动鼓温度变化模型,然后在试验的基础上建立一套适用于山区高速公路的避险车道设置位置理论计算方法,以此来确定避险车道的设置位置和设置间距. 相似文献
2.
长大纵坡路段是山区高速公路事故高发地。文章针对云南省镇康至清水河高速公路在连续长大纵坡路段存在的越岭特长隧道选择、爬坡车道设置、避险车道设置等关键性问题,从平均纵坡、运行速度模拟、货车下坡制动温度等方面进行分析,提出优化纵断面设计、合理选择越岭隧道方式、合理设置避险车道等措施,为山岭重丘区高速公路在连续长大纵坡路段的方案设计提供参考。 相似文献
3.
4.
5.
6.
7.
8.
9.
10.
广西隆林-百色高速公路是一条典型的山区高速公路,具有地形地质条件复杂、桥隧比例较高、施工难度大的特点。文章结合隆林-百色高速公路项目施工设计图的情况,提出了山区高速公路桥梁设计的要求,并对几个设计典型问题进行了初步的探讨,为山区高速公路桥梁设计提供参考。 相似文献
11.
12.
我国的桥涵设计规范中明确规定:桥上纵坡宜≯4%,但在山区公路设计中,由于纵向推力巨大,普通的梁式桥难以适应大坡度纵坡的要求。文章以广西水任南宁高速公路工程为例,介绍在高纵坡条件下修建斜腿刚构桥梁的设计特点以及其良好的适应性,为解决山区高等级公路建设中因纵坡过陡,造成的纵向推力过大的不利影响等问题提供借鉴。 相似文献
13.
针对艰险山区高速铁路隧道的防灾救援难题,文章依托秦岭马白山隧道,提出了适合该隧道的新型紧急救援站结构型式,并利用FDS软件模拟隧道内纵向通风时列车着火后的烟气扩散,确定了规范中尚未给出的紧急救援站隔离区长度参数。结果表明:(1)秦岭马白山隧道新型紧急救援站结构型式应包括疏散区、隔离区以及待避救援区;(2)利用FDS数值模拟时,在不考虑纵向通风下,烟气沿下坡方向的扩散长度为295 m;考虑沿下坡方向通风时烟气最远扩散长度为980 m,建议隔离区长度设置为1000 m。 相似文献
14.
Automated driving is gaining increasing amounts of attention from both industry and academic communities because it is regarded as the most promising technology for improving road safety in the future. The ability to make an automated lane change is one of the most important parts of automated driving. However, there has been little research into automated lane change maneuvers, and current research has not identified a way to avoid potential collisions during lane changes, which result from the state variations of the other vehicles. One important reason is that the lane change vehicle cannot acquire accurate information regarding the other vehicles, especially the vehicles in the adjacent lane. However, vehicle-to-vehicle communication has the advantage of providing more information, and this information is more accurate than that obtained from other sensors, such as radars and lasers. Therefore, we propose a dynamic automated lane change maneuver based on vehicle-to-vehicle communication to accomplish an automated lane change and eliminate potential collisions during the lane change process. The key technologies for this maneuver are trajectory planning and trajectory tracking. Trajectory planning calculates a reference trajectory satisfying the demands of safety, comfort and traffic efficiency and updates it to avoid potential collisions until the lane change is complete. The trajectory planning method converts the planning problem into a constrained optimization problem using the lane change time and distance. This method is capable of planning a reference trajectory for a normal lane change, an emergency lane change and a change back to the original lane. A trajectory-tracking controller based on sliding mode control calculates the control inputs to make the host vehicle travel along the reference trajectory. Finally, simulations and experiments using a driving simulator are conducted. They demonstrate that the proposed dynamic automated lane change maneuver can avoid potential collisions during the lane change process effectively. 相似文献
15.
16.
Jinxian Weng 《运输规划与技术》2013,36(8):811-822
Transition taper length plays a vitally important role in work zone safety operations because too short a transition taper length will result in higher accident risks and too long a transition taper length could increase traffic delay. This paper evaluates transition taper length under various traffic conditions and road geometries using collision avoidance analysis. The longitudinal distances for lane changing and emergency stopping manoeuvres are respectively calculated using collision avoidance analysis. The higher value between the longitudinal lane changing distance and emergency stopping distance is considered as the expected transition taper length. The comparison of transition taper lengths from the collision avoidance analysis and current empirical transition taper formulae shows that the collision avoidance analysis has the capability of evaluating transition taper lengths. This paper also contributes to providing theoretical supports for these empirical formulae. 相似文献
17.
18.
Traffic operations for new road layouts are often simulated using microscopic traffic simulation packages. These traffic simulation packages usually simulate traffic on freeways by a combination of a car-following model and a lane change model. The car-following models have gained attention of researchers and are well calibrated versus data. The proposed lane change models are often representations of assumed reasonable behavior, not necessarily corresponding to reality. The current simulation packages apply solely one specific type of model for car-following or lane changing for all vehicles during the simulation. This paper investigates the decision process of lane changing maneuvers for a variety of drivers based on a two-stage test-drive. Participants are asked to take a drive on a freeway in the Netherlands in a camera-equipped vehicle. Afterwards, the drivers are asked to comment on their choices related to lane and speed choice, while watching the video. This paper reveals that different drivers have completely different strategies to choose lanes, and the choices to change lane are related to their speed choice. Four distinct strategies are empirically found. These strategies differ not only in parameter values, as is currently being modeled in most simulation packages, but also in their reasoning. Most remarkably, all drivers perceive their strategy as an obvious behavior and expect all other drivers to drive in a similar way. In addition to the interviews of the participants in the test-drive, 11 people who did not take part in the experiment were interviewed and questioned on lane change decisions. Moreover, the findings of this study have been presented to various groups of audience with different backgrounds (about 150 people). Their comments and feedback on the derived driving strategies have added some value to this study. The findings in this paper form a starting point for developing a novel lane change model which considers four different driving strategies among the drivers on freeway. This is a significant contribution in the area of driving behavior modeling, since the existing microscopic simulators consider only one type of lane change models for all drivers during the simulation. This could lead to significant changes in the way lane changes on freeways are modeled. 相似文献
19.
A number of recent studies have examined the hypothesis of induced travel in an attempt to quantify the phenomenon (Hansen & Huang 1997; Noland, forthcoming). No study has yet attempted to adjust for potential simultaneity bias in the results. This study addresses this issue by the use of an instrumental variable (two stage least squares) approach. Metropolitan level data compiled by the Texas Transportation Institute for their annual congestion report is used in the analysis and urbanized land area is used as an instrument for lane miles of capacity. While this is not an ideal instrument, results still suggest a strong causal relationship but probably that most previous work has had an upward bias in the coefficient estimates. The effect of lane mile additions on VMT growth is forecast and found to account for about 15% of annual VMT growth with substantial variation between metropolitan areas. This effect appears to be closely correlated with percent growth in lane miles, suggesting that rapidly growing areas can attribute a greater share of their VMT growth to growth in lane miles. 相似文献