高速公路客运停靠站的设计研究

文章结合高速公路发展现状,系统地阐述了高速公路上客车停靠站建设的必要性,并根据高速公路的特点,研究了停靠站点的基本类型,分析了停靠站的线形及横断面几何设计方法。     

A two-stage-training support vector machine approach to predicting unintentional vehicle lane departure

Advanced driver assistance systems, such as unintentional lane departure warning systems, have recently drawn much attention and efforts. In this study, we explored utilizing the nonlinear binary support vector machine (SVM) technique to predict unintentional lane departure, which is innovative, as the SVM methodology has not previously been attempted for this purpose in the literature. Furthermore, we developed a two-stage training scheme to improve SVM's prediction performance in terms of minimization of the number of false positive prediction errors. Experiment data generated by VIRTTEX, a hydraulically powered, 6-degrees-of-freedom moving base driving simulator at Ford Motor Company, were used. All the vehicle variables were sampled at 50 Hz and there were 16 drowsy drivers (about 3 hours of driving per subject) and six control drivers (approximately 20 minutes f driving each). In total, 3,508 unintentional lane departures occurred for the drowsy drivers and 23 for the control drivers. Our study involving these 22 drivers with a total of more than 7.5 million prediction decisions demonstrates that (a) excellent SVM prediction performance, measured by numbers of false positives (i.e., falsely predicted lane departures) and false negatives (i.e., lane departures failed to be predicted), was achieved when the prediction horizon was 0.6 seconds or less, (b) lateral position and lateral velocity worked the best as SVM input variables among the nine variable sets that we explored, and (c) the radial basis function performed the best as the SVM kernel function.     

基于路阻函数的可变车道转换时机研究

针对“潮汐式”交通问题,探讨可变车道的实施流程和转换机理．基于BPR路阻函数建立了可变车道调整数量优化模型。该模型不仅能根据交通流状况计算出需要调整的车道数．而且可以针对不同的道路条件计算出可变车道适合的转换时机。最后,通过实例验证了模型的可行性。     

公交与右转混合型专用道仿真分析及效益评价

为解决设置公交专用道所带来的道路资源利用率低，相邻车道交通压力增大，专用道分时段开启致使社会车辆行驶混乱等问题，基于车种分离思想，提出一种公交车辆与右转车辆混合专用道的组织方式，允许公交车辆与右转社会车辆共用一条车道，以寻求保持公交优先与减少对社会车辆影响的平衡点。为论证该方案的可行性，首先，针对所研究的道路环境，提出了基于流量生成模型与配时优化模型的车道组仿真流程；随后，在考虑红灯时右转车辆行驶特性的前提下，建立了人均延误和车均延误的双指标评价矩阵模型；最后，分别在MATLAB和VISSIM仿真平台上，实现了对传统车道组、公交与右转混合型专用道车道组和公交专用道车道组3种方案的效益评价，并对其中的关键影响因素进行分析。仿真结果表明：所提出的公交与右转混合型专用道车道组的总体车均延误与人均延误在大多情况下处于较低水平，而公交专用道车道组和普通车道组也具有各自的优势区域；公交与右转混合型专用道的车道组织方式可以在保证社会车辆延误不明显增加的情况下，有效确保公交车辆的优先性，在一定条件下具有适用性，在工程实践中可作为公交专用道的过渡或替代方案。     

钢管压扁吸能式减速护栏方案可行性研究

基于钢管压扁吸能机理,通过在组合式护栏的横梁上设置钢管吸能构件,设计出一种适用于雅泸高速公路连续长大下坡路段的减速护栏。根据计算机仿真分析结果可知,车辆贴靠碰撞减速护栏时钢管压扁变形,使车辆的动能转化为吸能钢管的内能,可有效降低车速。设置吸能钢管可减小组合式护栏的最大动态变形量和横梁变形范围,对组合式护栏的碰撞后维护是有利的,吸能钢管在车辆碰撞护栏过程中的性能表现可满足设计要求。     

Increasing the capacity of signalized intersections by allocating exit lanes to turning movements

Unconventional intersection designs have been used to increase the capacity of intersections that are over‐saturated under conventional ones. However, existing unconventional designs typically require extra land space and their effectiveness often depends on drivers' familiarity with the uncommon operating rules. To overcome these challenges, we propose a new unconventional design, where movements that are mutually incompatible under the conventional design can be made compatible of each other by allocating exit lanes to them appropriately, thereby creating opportunities for capacity improvement. We develop a lane‐based capacity optimization model that incorporates the allocation of exit lanes as decision variables. The model is formulated as a Binary Mixed Integer Linear Programming problem, which can be efficiently solved by standard branch‐and‐bound algorithms. Numerical experiments show that significant capacity improvement can be obtained under our design. Besides proposing a new unconventional design, we also contribute to the literature of lane‐based signal optimization methods by providing a novel linear formulation for the latest, yet nonlinear, model described in Wong and Heydecker [Transportation Research Part B 45(4):667–681]. This improvement is methodologically beneficial as linear models are computationally more convenient than nonlinear ones. Copyright © 2017 John Wiley & Sons, Ltd.     

组合交通标志信息量阈值研究

针对组合交通标志信息量阈值缺乏量化依据的问题, 设计了包含指路标志与车道行驶方向标志的组合标志, 测定了被试者视认组合标志的正确率及反应时间, 得到组合标志的信息量阈值, 并通过试验对模拟结果进行了验证。分析结果表明: 车道数为3~7时, 被试者对组合标志视认的正确率分别为94.17%、93.13%、93.50%、87.50%、86.07%, 反应时间分别为2 437.54、2 514.01、2 634.18、3 600.75、3 836.21 ms; 指路标志中一条路名信息的视认反应时间相当于组合标志中5个箭头的视认反应时间, 均为0.5 s;指引图形较简单的组合标志信息量阈值为6条路名信息, 指引图形较复杂的组合标志信息量阈值为5条路名信息, 指路标志若与车道行驶方向标志组合设置则应相应减少路名信息。     

马驹桥互通式立交桥道路安全状况分析

随着我国高速公路的发展，互通式立交桥的道路安全问题目益受到关注．文中以京津塘高速公路马驹桥互通式立交桥为研究对象，结合该区域道路、交通以及事故统计数据，从立交形式、匝道线形和加速车道设置三个方面来分析安全状况，针对立交形式的完善和加速车道长度的确定进行了较为深入的探讨，并提出相应的改进措施，进而提高立交桥的安全水平．     

城市地下道路出入口变速车道长度设计研究

在介绍国内外立交出入口变速车道设计长度和国外地下道路出入口变速车道设计长度的基础上。根据我国地下道路的功能定位和分类,结合我国城市地下道路交通实际情况,提出我国地下道路出入口变速车道设计长度的取值建议,对我国地下道路的规划、设计和建设具有积极的作用。     

互通立交变速车道的探讨

变速车道是立交的重要组成部分,结合实际经验对变速车道及其中存在的一些问题进行分析讨论.