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Safety Evaluation of Stop-Sign Mounted Beacons—A Cross-Sectional Study 被引量:1
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作者 Amrita Goswamy Shauna Hallmark +1 位作者 Guillermo Basulto-Elias Michael Pawlovich 《Journal of Transportation Technologies》 2019年第1期95-108,共14页
Agencies in Iowa have utilized both overhead flashing beacons and stop-sign mounted beacons. Although several studies have shown that overhead flashing beacons are effective, some concerns have been raised about drive... Agencies in Iowa have utilized both overhead flashing beacons and stop-sign mounted beacons. Although several studies have shown that overhead flashing beacons are effective, some concerns have been raised about driver confusion. The main concern is that a driver may interpret a multiface flashing beacon with a red indication for their approach as an all-way stop control. As a result, the Iowa DOT has been advocating use of stop-sign mounted beacons rather than overhead flashing beacons. Since little information is available about this countermeasure, data for intersections with (treatment) and without (control) stop-sign mounted beacons were identified and a cross-sectional analysis conducted (due to few confirmable installation dates). Rural stop-controlled intersections with stop-sign mounted beacons in Iowa (USA) were identified (40 in total). Intersection characteristics such as number of approaches, intersection angle etc. were extracted. Additionally, characteristics of individual approaches such as roadway surface (gravel/paved), advanced stop-sign rumble strips, and advance signing were recorded. One or more control locations were manually selected for each treatment intersection based on matching roadway configuration, presence of lighting, advance stop line rumble strips, number of approaches, channelization, traffic volume, and proximity. Propensity scores were estimated to match 40 control locations for comparison. Negative binomial models for different injury combinations at nighttime and daytime were developed with an indicator variable for presence and absence of stop-sign mounted beacons. Presence of stop-sign mounted beacons was associated with a 5% - 54% reduction in nighttime crashes. Injury nighttime crashes decreased by 54% and total nighttime crashes reduced by 18%. 展开更多
关键词 stop-Sign Mounted Beacons SAFETY ANALYSIS NIGHTTIME crashes crash MODIFICATION FUNCTIONS
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Speed Reduction Mitigation Strategies on Rural Highways at Two-Way Stop Control Intersections and Curves
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作者 Ranjit Prasad Godavarthy Eugene R. Russell Babak Mirzazadeh 《Journal of Transportation Technologies》 2017年第4期423-437,共15页
Studies conducted on crashes at rural intersections of state highways and local roads/streets with two-way stop control have proved that the problem was likely poor judgment by the stopped driver on the minor approach... Studies conducted on crashes at rural intersections of state highways and local roads/streets with two-way stop control have proved that the problem was likely poor judgment by the stopped driver on the minor approach of the speed of an oncoming vehicle and/or safe gap in traffic on the major highway. Several mitigating strategies have been suggested and studied in various studies to improve safety at the two-way stop control rural intersections and at other rural highway segments. There are also several low-cost techniques used, mostly in foreign countries, to slow drivers on major highways as they enter small towns and villages, e.g., narrowing pavement lines, establishing visual gateways, etc. Lowered speeds would decrease crash severity. In this study, four strategies including solar speed display units, mobile speed trailers, optical speed bars, and colored pavement were tested and assessed in some locations in Kansas. The results of this research indicate that both solar speed display units and mobile speed trailers are effective in speed reduction at the desired points, but optical speed bars and colored pavements do not yield reliable results. Additional studies and longer term studies, should be conducted. 展开更多
关键词 RURAL Highway Safety RURAL crashes SPEED REDUCTION STRATEGIES Two-Way stop CONTROL
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柴油机-调距桨推进的舰船紧急制动性能仿真研究
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作者 蒲晓亮 钟涛 王艳真 《舰船科学技术》 北大核心 2023年第16期37-42,共6页
紧急制动是舰船的重要性能指标之一,为研究采用柴油机-调距桨推进的舰船紧急制动性能,本文对影响紧急制动的主要因素进行分析,以某巡逻船为对象,建立紧急制动仿真模型,分5种工况对制动性能进行仿真。结果表明,该船停船距离可控制在3倍... 紧急制动是舰船的重要性能指标之一,为研究采用柴油机-调距桨推进的舰船紧急制动性能,本文对影响紧急制动的主要因素进行分析,以某巡逻船为对象,建立紧急制动仿真模型,分5种工况对制动性能进行仿真。结果表明,该船停船距离可控制在3倍船长以内。分析可知,对于柴油机-调距桨推进的舰船,优化主机与螺旋桨的匹配控制策略和增加螺旋桨调距速率是优化紧急制动性能的主要途径,主机变转速策略比恒转速策略具有更好的紧急制动性能,调距桨的调距速率对紧急制动性能有较大影响,提高螺旋桨调距速率可有效减小紧急制动时间和距离。 展开更多
关键词 紧急制动 舰船 推进系统 调距桨 仿真
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超大型船舶安全纵向间距计算模型 被引量:8
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作者 明力 刘敬贤 王先锋 《中国航海》 CSCD 北大核心 2014年第4期40-43,共4页
在分析船舶倒车冲程的基础上,应用交通流跟驰理论,研究超大型船舶纵向间距,建立超大型船舶安全纵向间距计算模型,并分不同情形给出计算实例。运用该模型对渤海深水航路超大型船舶的安全纵向间距进行计算,并将结果与用其他模型计算的结... 在分析船舶倒车冲程的基础上,应用交通流跟驰理论,研究超大型船舶纵向间距,建立超大型船舶安全纵向间距计算模型,并分不同情形给出计算实例。运用该模型对渤海深水航路超大型船舶的安全纵向间距进行计算,并将结果与用其他模型计算的结果相比较。发现:在水深吃水比<1.5时,运用该模型算得的安全纵向间距较大,更能保证船舶安全;在水深吃水比≥1.5时,运用该模型算得的纵向间距较小,有利于提高船舶通过能力、充分利用水域资源。结果表明:该模型在计算船舶安全纵向间距方面更有优势。 展开更多
关键词 水路运输 超大型船舶 安全纵向间距 倒车冲程 交通流跟驰理论
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信号交叉口通行能力计算方法 被引量:45
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作者 徐立群 吴聪 杨兆升 《交通运输工程学报》 EI CSCD 2001年第1期82-85,共4页
目前计算城市交通网络信号控制交叉口通行能力的方法很多 ,适用范围各有不同。混合交通流是中国城市交通的特点。计算混合交通条件下城市信号控制交叉口的通行能力一直是众多交通领域专家学者研究的课题。以一个典型十字型信号交叉口为... 目前计算城市交通网络信号控制交叉口通行能力的方法很多 ,适用范围各有不同。混合交通流是中国城市交通的特点。计算混合交通条件下城市信号控制交叉口的通行能力一直是众多交通领域专家学者研究的课题。以一个典型十字型信号交叉口为例 ,分别用目前中国常用的三种计算通行能力方法 (冲突点法、停车线法、美国法 )计算该交叉口的通行能力 ,并将结果与实测通行能力进行比较。比较结果显示冲突点法算得的结果与实测结果最接近 ,而停车线法和美国法算得的结果都偏大。因此 。 展开更多
关键词 信号交叉口通行能力 混合交通流 冲突点法 停车线法 美国法
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全速倒车停船试验中主机熄火原因分析 被引量:2
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作者 周国强 甘少炜 雷伟 《船海工程》 2013年第6期121-123,共3页
针对新船建造完成后进行全速倒车停船试验时,容易发生主机熄火的问题,为避免导致齿轮箱损坏,通过对主机遥控系统逻辑指令执行过程的分析,查找出导致主机熄火的主要原因,提出几种避免主机易熄火的方法。
关键词 全速倒车 停船试验 紧急制动 主机遥控
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船舶操纵性评估体系构架设计 被引量:3
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作者 李秋珍 刘畅 《舰船电子工程》 2012年第12期101-103,135,共4页
针对船舶航行安全和操纵安全的需求,初步设计了船舶操纵性评估系统,给出了系统逻辑框架和评估指标体系。船舶操纵性评估模块是该船舶操纵性评估系统的核心,其评估指标体系由3个一级评估指标和11个二级评估指标组成,层次化特征明显。对... 针对船舶航行安全和操纵安全的需求,初步设计了船舶操纵性评估系统,给出了系统逻辑框架和评估指标体系。船舶操纵性评估模块是该船舶操纵性评估系统的核心,其评估指标体系由3个一级评估指标和11个二级评估指标组成,层次化特征明显。对部分二级评估指标给出了工程上可行的计算模型和评估准则。最后给出某货船的试验结果,验证了计算模型的实用性。 展开更多
关键词 船舶操纵性 评估指标 计算模型 紧急停船
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Random-parameters analysis of highway characteristics on crash frequency and injury severity 被引量:1
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作者 Bismark R.D.K.Agbelie 《Journal of Traffic and Transportation Engineering(English Edition)》 2016年第3期236-242,共7页
Factors that affect highway-related crash frequency and injury severity vary across observations. Using a methodology that does not account nor correct for heterogeneity in observed and unobserved crash factors across... Factors that affect highway-related crash frequency and injury severity vary across observations. Using a methodology that does not account nor correct for heterogeneity in observed and unobserved crash factors across highway segments may lead to biased and inconsistent estimated coefficients, thus resulting in erroneous inferences. The present paper demonstrates the use of random-parameters models to facilitate and enhance how crash factors affect crash frequency and injury severity along a highway segment. The results indicate that a unit increase in the presence of stop sign along a highway segment reduces crash frequency by 2.471 for 87.24% of the roadway segments. For the remaining 12.76% of the roadway segments, crash frequency is increased by the same margin. Using the random-parameters multinomial logit model, the result indicates that, for 90.89% of the observations, the presence of a stop sign on a highway segment increases the probability of the injury outcome. For 9.11% of the observations, the presence of a stop sign on a highway segment reduces the probability of the injury outcome, and the marginal effect value across observations is 0.0017. Vertical grades greater than 5% increase crash frequency for 58.46% of the highway segments, and decrease for 41.54% of the highway segments by 0.121 for one unit increase in vertical grades. 展开更多
关键词 Random -parameters Multinomial logit model Negative binomial HETEROGENEITY Highway crash Highway segment Vertical grade stop sign Marginal effects
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导管调距桨全回转拖轮停船运动建模与仿真 被引量:3
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作者 杨景 任俊生 +1 位作者 张钊 赵梦龙 《大连海事大学学报》 CAS CSCD 北大核心 2017年第2期13-19,共7页
针对配备了双导管调距桨的全回转拖轮进行紧急停船运动仿真.基于分离型建模思想,建立全回转拖轮的停船运动数学模型.采用塔格尔特剩余阻力图谱获得不同弗汝德数下的剩余阻力系数,建立适用于常速域和低速域的拖轮阻力模型.通过修正后的JD... 针对配备了双导管调距桨的全回转拖轮进行紧急停船运动仿真.基于分离型建模思想,建立全回转拖轮的停船运动数学模型.采用塔格尔特剩余阻力图谱获得不同弗汝德数下的剩余阻力系数,建立适用于常速域和低速域的拖轮阻力模型.通过修正后的JD7704导管+Ka4-70螺旋桨图谱与荷兰船模试验水池最新提出的C4-40调螺旋桨图谱,获得不同水动力螺距角与螺距比下的推力系数,建立适用于导管调距桨实际操纵工况的推力模型.仿真结果显示,所建模型可满足拖轮操纵模拟器中全回转拖轮紧急停船运动精度的要求. 展开更多
关键词 导管调距桨 全回转拖轮 紧急停船 建模与仿真
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