行人与轿车正碰后卷绕型运动形态仿真研究*

为研究行人与轿车正碰后卷绕型运动形态规律以及行人损伤情况,基于PC Crash和MADYMO软件进行仿真分析。分析不同发动机罩倾斜程度对行人抛距的影响,以及不同车速、行人走向、前挡风玻璃倾角对行人头部、胸腔的损伤影响,最后通过CIDAS数据库中的3起真实案例进行验证。结果表明:分段抛距公式不仅能反映行人抛距变化趋势,而且在2个分段范围内均能较好地拟合实际抛距,平均误差为4.23%,实际案例验证的结果误差在5%以内,证明实验方法的准确性。     

A case study on period vehicle routing in a refuse collection system

Period vehicle routing, a multi-period extension of the capacitated vehicle routing problem, is the problem of determining a service combination of each customer as well as the vehicle routes in each period of the planning horizon while satisfying the restrictions on the vehicle capacity and the travel distance (time). The problem can typically be found in refuse collection systems in which end-of-life products or wastes are collected and moved to the facilities where further treatment is taken care of. In this study, we report a case study on the problem for the objective of minimising the fleet size, i.e. the maximum number of vehicles simultaneously required over the planning horizon. To solve the problem, we adopt the two-stage heuristic in which an initial solution is obtained by assigning a service combination to each collection point, and then it is improved by changing the service combination assigned to each collection point. Computational experiment was done on the case data and significant improvement over the conventional method is reported.     

“后补贴”时代地方政府新能源汽车补贴策略研究

新能源汽车补贴是政府为了发展新能源汽车产业所采取的一项激励政策。现有文献虽在微观层面上研究了政府补贴对新能源汽车推广的影响,但多将补贴政策限定为固定额度的政府补贴,未考虑中国特殊的两级政府补贴政策尤其是地方政府补贴对新能源汽车推广的影响,且在补贴政策的设计上未与新能源汽车的实际推广目标相结合。基于"后补贴"时代的地方政府既要实现新能源汽车推广目标又要保证补贴政策合理退坡的双重现实要求。本文依据当前中央政府为新能源汽车提供固定补贴,地方政府提供配套比例补贴以及制定价格补贴比例上限的现实情形,综合考虑新能源汽车成本、充电桩建设情况、消费者初始效用、中央政府补贴等因素对地方新能源汽车推广的影响,构建了地方政府为实现既定新能源汽车推广目标的最优补贴策略模型。研究表明:(1)对于不同效用水平的消费者,地方政府价格补贴比例上限和配套比例补贴对新能源汽车零售价格所起的作用不同;(2)地方政府补贴政策只有在小于或等于其最优配套比例或价格补贴比例上限时才会对新能源汽车推广产生正向影响。最后,还结合北京新能源汽车推广的实际情况进行了数值模拟,给出了在不同新能源汽车成本、充电桩建设情况、消费者初始效用下北京市政府为实现新能源汽车推广目标的最优补贴策略。数值模拟结果表明,当前北京新能源汽车存在地方配套比例过高、价格补贴比例上限过高等问题。在后补贴时代,北京市政府可依据新能源汽车成本下降、充电设施逐步完善、消费者初始效用提升等因素变化,对补贴进行适当退坡。数值模拟表明,所构造的最优补贴策略模型对后补贴时代地方政府新能源汽车补贴政策的制定具有较高的参考价值。     

行驶速度对机动车尾气排放的影响

利用COPERTIV模型计算和车载尾气测量系统实测得到不同行驶速度下的机动车尾气排放因子,并分析不同车型不同排放标准等级车辆的行驶速度对排放的影响。调查研究北京市城区路网早高峰、平峰、晚高峰和夜间的车流量、车型构成、行驶速度,基于ArcGIS建立平均车速和行驶里程的网格分布数据库,并对比车速修正前后不同道路类型不同污染物的排放强度。结果表明,基于COPERT IV模型和车载测量系统计算的小客车NOx和HC排放因子随车速的变化趋势类似,均随车速的增加呈现U型分布;柴油公交车与柴油卡车NOx和HC排放因子随着车速的升高而减小。4个时间段平均车速大小排序为：夜间（44 km·h-1）> 晚高峰（34 km·h-1）> 平峰（32 km·h-1）> 早高峰（28 km·h-1）。车速修正后CO和HC的排放量上升,上升幅度分别为10.6%~11.8%和8.8%~9.2%,NOx和PM排放量下降,下降幅度分别为22.1%~23.3%和12.7%~13.5%。     

水雾荷电特性的试验研究

通过试验研究,总结出环状电极水雾荷电的特点和规律,为水雾荷电应用于湿式除尘提供了科学的依据。     

汽车电动助力转向装置的安全性探讨

电动助力转向装置是汽车上一种新的助力转向系统装置 ,近年来在国内外发展迅速 ,由于它采用了可编程电子控制装置 ,在带来灵活性的同时也存在着安全隐患。在分析这种产品特殊性的基础上 ,笔者结合电子控制装置的特点 ,指出了事关安全性的因素 ,提出了处理安全性的措施 ,并讨论了几个事关安全性的具体问题。研究结果表明 :现有标准不能够满足电动助力转向装置安全性的需要 ;并提出了对电动助力转向装置进行安全性测评的思想。研究工作对电动助力转向装置的开发以及评价具有参考意义。     

机动车辆阻火罩的开发应用

系统阐述了新型机动车辆阻火罩的工作原理、结构及其功能，并对该阻火罩进行了综合测试，同时将其与原有阻火罩的各项性能进行了对比分析。     

Characteristics of Moose-vehicle Collisions in Anchorage, Alaska, 1991–1995

Moose have successfully adapted to Anchorage's urban environment, using greenbelt areas for shelter, forage, and protection from nearby predator populations. However, the proximity of moose to people poses unique hazards: a motor vehicle colliding a moose may cause significant injury and vehicle damage. The annual Moose Vehicle Collision (MVC) rate increased during the study period from 40 to 52 MVCs per 100,000 registered vehicles in Anchorage, a significant (X² = 7.8, p < 0.01) increase of 23%. Of 519 reported MVCs, 23% resulted in injury to 158 people, with no human fatalities. Collisions were 2.6 times more likely to have occurred in the dark (n = 375, [72%]) than during daylight hours. An MVC on a dry road was twice (95% CI: 1.29, 3.08) as likely to have resulted in an injury as an incident on a slick road. MVCs may be prevented by: reducing speed limits around greenbelt areas, brighter vehicle headlights, placement of street lights in known moose areas, underpasses for wildlife at known crossings, and snow removal to reduce berm height in areas of high moose concentrations. Published by National Safety Council and Elsevier Science Ltd     

油田企业交通HSE管理

介绍了油田企业交通HSE管理的整体思路,从驾驶员、车辆、道路、运行等方面阐述了HSE管理的具体内容。     

Risks older drivers pose to themselves and to other road users

Problem

Studies have shown that older drivers have high death rates and lower rates of involvement in crashes that kill others; but most studies have not considered drivers' responsibility for their crashes, and many have considered only one particular measure of risk.

Method

This study examines risks that drivers of various ages pose to themselves and to others on per-driver, per-trip, and per-mile bases, taking responsibility for crashes into account, using United States fatal crash data from 1999 through 2003 and travel estimates from 2001.

Results

Relative to other age groups, drivers aged 85 and older face the highest risk of their own death, whereas teens pose the greatest risk to passengers, occupants of other vehicles, and non-motorists.

Discussion

The oldest drivers pose more risk to other road users than middle-aged drivers do; the degree of their excess risk depends strongly upon how risk is measured.

Impact on industry

These results demonstrate the importance of keeping clear the meaning and implications of various risk measures.