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121.
In this paper we investigate the effect of the Los Angeles transit strike on highway congestion through analysis of highway sensor data, using both a before-and-after comparison, and a control group comparison. We found that average 5:00 a.m. to 10:00 p.m. traffic speeds declined by as much as 20% during the strike, and the average length of the rush period increased by as much as 200%, even though increases in traffic were small, despite the fact that transit riders constitute a small fraction of the traveling population. Speeds declined the most at locations upstream from the places where queues normally end. We believe that highways are especially susceptible to congestion during strikes because travelers have little opportunity to adjust and equilibrate their travel patterns, as is possible during ordinary periods of traffic growth.  相似文献   
122.
车用电涡流缓速器试验方法的探讨   总被引:2,自引:0,他引:2  
在分析比较国外相关的辅助制动法规和研究车用电涡流缓速器基本性能要求的基础上,探讨了车用电涡流缓速器的台架试验方法,研制了电涡流缓速器试验台。介绍了所研制试验台的工作原理,提出了试验方法和试验步骤。该试验方法的提出为国内制定电涡流缓速器相关标准提供了一定的理论依据。  相似文献   
123.
任志广 《汽车工程》2002,24(4):356-358,293
介绍了中意车前围改型的全部过程,对概念设计、全尺寸模型的制作、涂装评审等方面作了全面的阐述,以两个1:1模型为例介绍了三维造型中经常遇到的难点问题和解决方法。  相似文献   
124.
Lythgoe  W.F.  Wardman  M. 《Transportation》2002,29(2):125-143
Rail access to airports is becoming increasingly important for both train operators and the airports themselves. This paper reports analysis of inter-urban rail demand to and from Manchester and Stansted Airports and the sensitivity of this market segment to growth in air traffic and the cost and service quality of rail services. The estimated demand parameters vary in an expected manner between outward and inward air travellers as well as between airport users and general rail travellers. These parameters can be entered into the demand forecasting framework widely used in the rail industry in Great Britain to provide an appropriate means of forecasting for this otherwise neglected market segment. The novel features of this research, at least in the British context, are that it provides the first detailed analysis of aggregate rail flows to and from airports, it has disaggregated the traditional generalised time measure of rail service quality in order to estimate separate elasticities to journey time, service headway and interchange, and it has successfully explored departures from the conventional constant elasticity position.  相似文献   
125.
Observing the rhythms of daily life: A six-week travel diary   总被引:2,自引:0,他引:2  
  相似文献   
126.
This paper presents vibration control of a tracked vehicle installed with electro-rheological suspension units (ERSU). As a first step, an in-arm type ERSU is designed, and its spring and damping characteristics are evaluated with respect to the intensity of electric fields. Subsequently, a 16 degree-of-freedom model for a tracked vehicle equipped with the proposed ERSU is established followed by the formulation of a neuro-fuzzy controller. This controller takes account for both ride quality and steering stability by adopting a weighting parameter between two performance requirements. The parameter is appropriately determined by employing a fuzzy algorithm associated with two fuzzy variables: the vertical speed of the body and the rotational angular speed of the wheel. Control performances to isolate unwanted vibration from bump and random road excitations are evaluated through computer simulations. In addition, maximum speed of the vehicle with 6 Watt power absorption is investigated with respect to the road roughness.  相似文献   
127.
轿车柴油机   总被引:7,自引:0,他引:7  
概述了轿车柴油机的发展历史和技术现状 ,介绍了国外典型产品的特点和技术参数以及轿车柴油机在国外的市场销售状况 ,预测了轿车柴油机的发展趋势 ,提出了我国发展轿车柴油机的策略建议  相似文献   
128.
陈宏伟  王铁山  曲波  任露泉 《汽车工程》2000,22(2):115-119,124
本文以奥迪100盘式制动器为研究对象,建立了一种可模拟制动压力-力矩响应迟清点特性的可变线性模型,首先,介绍在JF-132型汽车制动器试验台上进行防抱制动器模拟试验的方法,其次,在获得大量试验数据的基础上,运用曲线拟合和优化技术,建立制动压力-力矩关系的线性模型,心滞模型为线笥模型,最后,在相同制动压力输入的前提下,把模型的理论计算民试验结果进行对比分析了模型的有效性和精确性。  相似文献   
129.
For purpose of simulation of vehicle dynamics, a physical model of an automotive shock absorber has been developed and implemented in several software packages for multibody simulations. In the present paper, the damper model structure is shortly elaborated together with some measurement and estimation techniques to retrieve the model parameters, possibly from dynamometer measurements only. These techniques are illustrated on a shock absorber normally used on the front suspension of a BMW series 7.  相似文献   
130.
REGULATIONOFPRODUCTIONOFPARATHYROIDHORMONE-RELATEDPEPTIDE(PTHrP)ANDEXPRESSIONOFITSmRNAINAHUMANLIVER-DERIVEDCELLLINELiHusong;P...  相似文献   
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