交通事故的时间分布规律

交通事故已成为威胁人民生命、财产安全的社会公害之一。笔者利用国内外有关交通事故数据进行统计分析,对交通事故发生的时间特征进行研究,为改善交通安全状况提供理论基础。运用统计分析、对比分析方法,分析国外不同国家和我国交通事故年时间分布规律的波峰曲线,得出我国交通事故逐年上升的势头有望得到遏制,使人们对战胜交通事故灾害充满信心。分析交通事故小时时间分布曲线,得出交通事故高峰小时出现在交通量高峰小时之后,两者不重合,死亡高峰时段(危险时段)多发生在夜晚等结论。该结论对采取针对不同时间内降低交通事故的教育、管理、工程等安全对策具有实用价值。     

SOFM神经网络在道路交通事故分类评价中的应用

随着我国道路交通需求的持续增长和交通建设的快速发展,交通环境和条件有了很大改善,但交通事故仍频频发生,且呈不断增多的趋势,安全已成为交通管理当中一个不容忽视的问题。为了减少交通事故发生次数,降低事故损失程度,需要对交通事故进行分类管理,以便针对不同种类和特征的交通事故采取专门的措施。笔者应用SOFM(自组织特征映射)神经网络对不同原因的道路交通事故进行了分类评价,并根据实际数据的计算和分析提出了相应的防护和控制措施。     

Toleration of Traffic by Vegetation: Life Form Conclusions and Summary Extracts from a Comprehensive Data Base

/ An exhaustive search of the literature for foot and vehicle traffic impacts on vegetation has yielded more than 400 citations, two thirds of which held sufficient detail to be usefully distilled into a personal-computer data base. A total of 1444 individual observations involving 737 species that were trampled are included. Compromises were made in the depth of entry detail and to allow comparability among data. Inconsistent, generally short-term, experimental practices disallowed formal statistical analyses. Within those constraints, graminoids emerged with the highest mean resistance and resilience among life-forms. Climbers and cactoids ranked lowest in these categories. The herbaceous, typically broader-leaved (forb) life-form appeared most likely to suffer immediate losses. Shrubs and trees had the longest-lasting decreases in diversity following traffic impact. All life-forms had sensitive species. The greatest general species and individual plant losses take place in the first few passes by feet, wheels, or tracks. Plant and soil damage increases with the amount of weight and power applied. Greater soil moisture and/or deeper overstory shading magnify those impacts. Additional precepts may become apparent to data-base users through increased ease in making comparisons.KEY WORDS: Vegetation; Trampling; Vehicles; Traffic; Resistance; Resilience; Data base     

Environmental effects of soil property changes with off-road vehicle use

The effects of off-road vehicles (ORVs) on the physical and chemical properties of 6 soil series were measured at Hollister Hills State Vehicular Recreation Area in central California. Accelerated soil erosion and the alteration of surface strength, bulk density, soil moisture, temperature, and soil nutrients were quantified to gain an insight into the difficulty of revegetating altered, or modified, areas.Erosion is severe at Hollister Hills, particularly in coarse grained soils on steep slopes. Erosion displaced 0.5 and 3.0 metric tons per square meter on 2 trails on gravelly sandy loam, and 0.3 metric tons/m² from a trail on sandy loam. The surface strength and bulk density increased while the soil moisture decreased in gravelly sandy loam, coarse sandy loam, sandy loam, and clay. Clay loam had an increased surface strength with variably increased bulk density and no decrease in soil moisture. Diurnal temperature fluctuations increased and organic material and soil nutrients decreased in soil modified by vehicles.These property changes increase the erosion potential of the soil, impede germination of seedlings, and slow natural revegetation. Management methods in ORV-use areas should include planning trails by prior application of the universal soil loss equation and soil surveys, trail closure before complete loss of the soil mantle, and revegetation of closed areas.     

Turning gap acceptance decision-making: the impact of driver distraction

PROBLEM: A number of studies have found that use of in-car phones by drivers can interfere with the cognitive processing necessary for making appropriate and timely vehicle control decisions. However, the specific linkage between communication-based distraction and unsafe decision-making has not been sufficiently explored. METHOD: In a closed-course driving experiment, 39 subjects were exposed to approximately 100 gaps each in a circulating traffic stream of eight vehicles on an instrumented test track that was wet about half the time. The subjects were at the controls of an instrumented car, which was oriented in a typical left-turn configuration (traffic-crossing situation in North America) and with parking brake on and the transmission in neutral. The subjects were instructed to press on the accelerator pedal when they felt that a gap was safe to accept. Their performances were monitored and incentives were provided for balancing safe decision-making with expeditious completion of the task. For half of the gap exposures (randomly assigned), each subject was required to listen and respond to a complex verbal message. RESULTS: When not distracted, the subjects' gap acceptance judgment was found to be significantly influenced by their age, the gap size, the speed of the trailing vehicle, the level of "indecision," and the condition of the track surface. However, when distracted, the subjects did not factor pavement surface condition into the decision process. On wet pavement, the subjects were judged to have initiated twice the level of potential collisions when distracted by the messages that they did when not distracted. DISCUSSION: Listening/responding to verbal messages may reduce the capacity of drivers to process adequately all the important information necessary for safe decision-making. The effects of the messages in our study seemed to cause the subjects to misjudge gap size and speed information when operating under the additional disadvantage of adverse pavement condition. SUMMARY: Attention to complex messages while making decisions about turning through gaps in an on-coming vehicle stream was associated with significantly increased unsafe decision making by subjects in our experiment when the additional complexity of wet surface condition was introduced. IMPACT ON INDUSTRY: While the results reflected a somewhat artificial situation where the measure was signaled intention to act rather than the act itself, nevertheless, they do strongly suggest a scenario in which mental distraction could contribute to crash risk. With the rapid proliferation of telematics in the vehicle market, even with the laudable objectives represented by the Intelligent Transportation Systems initiative, there is a danger of the primary task of the driver being subordinated to a perceived need to enhance information flow to/from the external "world." Industry and governments need to work together to ensure that apparently desirable in-vehicle communication improvements do not compromise safety.     

秦沈客运专线工程建设办公信息系统的安全设计

从秦沈客运专线工程建设办公信息系统的网络和系统内部安全机制出发 ,提出了大型交通工程项目办公自动化系统信息安全技术的理论和设计思路。系统而成功的运行为今后同类项目的安全设计提供了一种新的思路并有一定的参考价值。     

任意点置镜测量既有曲线方法的研究

整正既有曲线是既有线提速改造和工务设计大修中的主要工作之一。传统的整正既有曲线的现场测量工作是将测量仪器置镜在曲线的钢轨上进行。这种方法既不安全 ,又容易引发交通事故 ,且工作效率极低。为改进传统的整正既有曲线的现场测量工作 ,满足火车提速和铁路建设的需要 ,提出采用置镜任意点的测量方法 ,对减少交通事故的发生和提高工作效率均具有十分重要的现实意义     

论降低我国道路交通事故致死率的措施

阐述我国交通事故人身伤害的严重性 ,参照发达国家交通安全经验 ,提出了减轻伤害、降低交通事故致死率的措施     

基于智能交通运输系统(ITS)的交通安全控制体系研究

道路交通事故是当今世界最严重的公害之一 ,道路交通安全问题也受到世界各国的广泛重视。近十年 ,全球发展较快的智能交通运输系统 (ITS)使传统的交通运输状况大为改善 ,大大地提高了现有道路网的通行能力和交通运输的安全性 ,削弱或消除了以往诱发交通事故的不安全因素 ,有效地减少了交通事故的发生。笔者在简述了ITS的应用概况、基本功能以及智能汽车理论研发内容的基础上 ,论述了以ITS技术为基础的交通安全控制体系框架及其功效 ,阐明了我国快速发展ITS技术对提高道路交通安全水平具有重要的战略意义。     

关于道路交通安全现代化进程的研究

道路交通安全是世界各国极为关注的问题之一。笔者从交通安全角度将道路交通现代化进程分为第一次现代化和第二次现代化两个阶段。根据人—车—路三者关系协调程度的变化 ,又可将第一次交通现代化阶段分为起步期、发展前期、发展后期、成熟期和过渡期等 5个时期。各个时期的交替可根据交通事故死亡人数的变化趋势来划分。笔者通过对日本 4 0多年来和我国 10多年来交通现代化的发展历程进行了对比分析 ,认为我国道路交通现在处于第一次交通现代化阶段的发展前期 ,今后交通事故死亡人数有可能进一步大幅度上升。为此 ,应该加大对传统交通手段的改造和交通现代化的投入 ,以防出现道路交通事故极其严重的局面。