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41.交通网络性能的约束微积分的代数方法:道路网络微积分
[信息传输、软件和信息技术服务业,交通运输、仓储和邮政业] [2015-08-05]
An application of the basic results of deterministic network calculus theory to road traffic flow theory is presented. Network calculus is a theory based on min-plus algebra. This calculus uses algebraic techniques to compute performance bounds in communication networks, such as maximum end-to-end delays and backlogs. The objective of this paper is to investigate the application of those techniques for determining performance bounds on road networks, such as upper bounds for travel times. A traffic model is proposed for cars moving in a single-lane ring road without passing. The model is compatible with network calculus theory and permits derivation of an upper bound of the travel time of cars on the road. An approach for extending the model to calculate upper bounds for the travel times of cars on paths passing through intersections in a whole network is also proposed.
关键词:汽车;交通网络;微积分
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42.轨道车管理维护:美国交通行业实践和改进机会
[交通运输、仓储和邮政业] [2015-08-05]
This report surveys the state-of-practice of transit railcar maintenance management and fleet management practices. It emphasizes a lifecycle management approach to fleet management. It also emphasizes the role of performance improvement programs and introduces Reliability-Centered Maintenance and Total Productive Maintenance as key examples of performance improvement approaches. The report also covers planning and performance measurement for rail fleet maintenance, as well as the role of supporting business processes and systems in railcar maintenance, including new vehicle procurement, facility upgrades, maintenance information systems, and purchasing and materials management.
关键词:汽车;管理维护;交通成本
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43.2013警察车辆评估项目建模
[汽车制造业] [2015-08-05]
The Michigan State Police Vehicle Test Team is pleased to present the results of the 2013 model year Police Vehicle Evaluation. This year we tested thirteen vehicles in total, and four motorcycles. All of the cars were tested with a clean roof (no overhead light or light bar) and without A pillar mount spotlights. We believe this is the best way to ensure all of the vehicles are tested on an equal basis. Remember that once overhead lights, spotlights, radio antennas, sirens, and other emergency equipment are installed, overall performance may be somewhat lower than we report. Each vehicle was tested with the tires that are available as original equipment on the production model. Specific tire information for each vehicle is available in the Vehicle Description portion of this report. All vehicles listed in this report were equipped with electronic speed limiters. Motorcycles were tested with equipment installed as provided by their respective manufacturer. Harley-Davidson chose to test their bikes with minimal equipment. BMW, and Victory chose to test their bikes with the majority of the equipment installed.
关键词:汽车;警车;交通安全
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44.基于Fisher判别分析的铁路车辆悬挂系统故障诊断
[汽车制造业] [2015-08-05]
In this paper, fisher discriminant analysis (FDA) is used for fault isolation and diagnosis in rail vehicle suspension systems. The suspension systems are equipped with acceleration sensors in the corners of the car body and the two bogies. The faults considered are the lateral damper faults and the lateral spring faults in suspension systems. FDA provides an optimal projection space on the basis of the training data including the fault data and normal data to classify the test data. A vehicle model is built by SIMPACK/MATLAB software with real parameters to obtain the simulation data and the effectiveness of the proposed method is demonstrated by simulation.
关键词:汽车;故障检测;判别分析
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45.筛选自然驾驶研究数据研究重要事件安全性
[交通运输、仓储和邮政业] [2015-08-05]
This study responds to the need to screen events observed during naturalistic driving studies to derive a set of crashes and near crashes with common etiologies; these crashes are referred to as "well-defined surrogate events." Two factors are critical to the identification of these well-defined surrogate events: selection of screening criteria and the designation of a time window to be used for event search. Testing conducted by using an algorithm developed in a previous study is described. The algorithm allows for the use of a range of search criteria to identify events with common etiology from unrefined naturalistic driving data. A range of kinematic search criteria was used to screen events, including lateral and longitudinal accelerations averaged over different time windows and characterized by average as well as maximum values during a time window. The testing was conducted with data from road departure events collected during a concluded 100-car naturalistic driving study. Fifty-one nonintersection and 12 intersection-related run-off-road events were included in the testing. Different sets of events were identified with different search criteria and different time windows. Diagnostic tools borrowed from medicine identified the best screening criteria and tune windows. The methods allowed for enhanced identification of well-defined surrogates by using covariates such as driver attribute context and driver fatigue. The research illustrates a flexible procedure that uses a variety of statistical methods shown to effectively screen crashes and near crashes.
关键词:汽车;安全性;驾驶数据
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46.轻型汽车技术、二氧化碳排放和燃油经济性的趋势:1975年到2012年
[水利、环境和公共设施管理业,汽车制造业] [2015-08-05]
This report summarizes key trends in carbon dioxide (CO2) emissions, fuel economy, and CO2- and fuel economy-related technology for gasoline- and diesel-fueled personal vehicles sold in the United States, from model years (MY) 1975 through 2012. Personal vehicles are those vehicles that EPA classifies as cars, light-duty trucks, or medium-duty passenger vehicles. The data in this report cover the MY 1975-2012 timeframe, supersede the data in previous reports in this series, and, for many important reasons, should not be compared with data from previous years editions of this report. Most CO2 emissions and fuel economy values in this report have been adjusted to reflect 'real world' consumer performance and therefore are not comparable to CO2 emissions and fuel economy standards.
关键词:汽车;轻型汽车技术;二氧化碳
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47.通用汽车双向控制的特点和最优速度模型:协调连接车辆环境中驾驶的影响
[汽车制造业] [2015-08-05]
In natural traffic flow, the information from preceding vehicles predominantly determines driver behavior. With connected vehicle technologies, drivers can receive information from both preceding and following vehicles. This information creates new opportunities for vehicle coordination and control at the microscopic level on the basis of bidirectional information. Although bidirectional car-following models have been studied since the 1960s, most existing car-following models, especially those used by adaptive cruise control technologies, are still forward-only car-following models. This paper serves as a first step toward the use of bidirectional car-following models for microscopic vehicle coordination and control. The focus is on the study of the models' general control characteristics and impact on traffic flow stability. A general bidirectional control framework is proposed to convert any car-following model into its bidirectional form. Four representative General Motors and optimal velocity car-following models are reformulated and calibrated against field vehicle trajectory data collected in the next-generation simulation program (NGSIM). The bidirectional control characteristics of the selected models were evaluated by tuning of the percentage of backward information considered in the final car-following decision. The evaluation uses forward versus backward acceleration diagrams and a ring road stability analysis of equilibrium states obtained from NGSIM data. The results indicate that the increase in the contribution of backward information may help alleviate traffic congestion and stabilize traffic flow. An operating range of the backward information contribution of between 5% and 20% is recommended to ensure that the resulting models are still physical and realistic for both free-flow and congestion situations.
关键词:汽车;通用汽车;安全
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48.基于车对车安全应用程序通信对优先级轻型汽车撞车前的场景描述
[汽车制造业] [2015-08-05]
A template of pre-crash scenarios is presented to depict national crash statistics and kinematic information of time-to-collision for the design of appropriate crash countermeasures based on vehicle-to-vehicle (V2V) communications. This template serves the development of functional requirements, performance specifications, test procedures, and benefits estimation for potential light-vehicle V2V safety applications. A set of ten pre-crash scenarios is suggested as a priority list to be addressed by V2V technology for light vehicles (i.e., passenger cars, vans and minivans, sport utility vehicles, and light pickup trucks with gross vehicle weight ratings of 10,000 pounds or less). This report presents the time-to-collision equations as well as the crash statistics for each of the ten priority scenarios based on data available in the General Estimates System, National Motor Vehicle Crash Causation Survey, and Event Data Recorder databases.
关键词:汽车;安全通信;撞车
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49.爱荷华州关于死亡评估和控制评价的报告:分心驾驶造成柴油机械机动车事故
[公共管理、社会保障和社会组织,交通运输、仓储和邮政业] [2015-08-05]
A 37-year-old diesel mechanic employed by a railroad transportation company died when his loaded utility truck collided with the rear of a semi-trailer on a four-lane interstate highway. The mechanic was driving at highway speed during daylight hours when he failed to stop in time and struck the semi, which was moving slowly in traffic that had backed up due to a car fire two miles downstream. There was severe damage to the mechanic's truck, with underside of the cab and intrusion up to the right rear tires of the trailer ahead. The force of the collision caused a chain reaction, pushing the struck tractor-trailer forward into a second tractor-trailer that had stopped in backed up traffic. Fire and rescue responders arrived from the nearby town located four miles away. The mechanic, who was wearing a safety belt, suffered blunt force trauma as a result of the collision and was pronounced deceased at the scene. He was extricated by mechanical means from the truck cab and was found holding a cell phone. Law enforcement officers' examination of the phone activity revealed the mechanic had exchanged several voice/text messages prior to the crash and was initiating a voice/text message application at the time of the collision. The driver's failure to notice the tractor trailer ahead and stop in time was attributed to texting. Drivers of the other two vehicles were not severely injured.
关键词:汽车;交通安全;机动车事故
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50.2011年乘员约束使用:国家乘员保护使用控制的交叉研究调查结果
[交通运输、仓储和邮政业] [2015-08-05]
This report presents results from the 2011 National Occupant Protection Use Survey (NOPUS) Controlled Intersection Study. NOPUS is the only nationwide probability-based occupant restraint use survey. The National Center for Statistics and Analysis of the National Highway Traffic Safety Administration conducts this survey annually. The 2011 NOPUS found that restraint use for all children from birth to 7 years old increased significantly from 89 percent in 2010 to 91 percent in 2011. Significant increases in child restraint use in 2011 occurred among children traveling in vans and SUVs, in the Northeast, and during weekends. Among occupants 8 and older, seat belt use in front seats continued to be lower among 16- to 24-year-olds than other age groups. Seat belt use in rear seats stood at 74 percent in 2011.
关键词:汽车;交叉研究;交通安全