普通公路驾驶员期望车速调查分析与建模

为了解普通公路驾驶员的车速选择机理,对驾驶员进行了期望车速问卷调查,对驾驶员的个人信息、车辆特征、以及驾驶员对超速10%的认可态度等可能影响期望车速的因素进行了重点调查。根据限速值的不同,分80、60和40 km/h 3个等级进行了调查,并为各等级公路选取了代表路段,由具有类似驾驶经历的驾驶员认真填写。对435份有效问卷进行了分析,发现期望车速广泛存在于驾驶员心中,驾驶员在行车过程中会使车速尽量维持在期望车速附近。期望车速主要受限速值、驾驶员的驾龄、对超速10%的态度以及车辆性能等因素的影响,驾驶员的性别和年龄对期望车速的影响不显著。采用逐步回归法,得到了期望车速的计算方法。对期望车速的特点、交通安全措施以及调查方案中可供改进的地方进行了总结。     

Profile-speed data-based models to estimate operating speeds for urban residential streets with a 30 km/h speed limit

A speed limit of 30 kilometres per hour (km/h) has been widely introduced for urban residential streets to ensure traffic safety and allow these streets to fulfil other intended functions. However, excessive speeds on these roads are very common, causing traffic safety problems and threatening the liveability of neighbourhoods. An effective and active way to deal with speeding is the application of a performance-based design approach, as mentioned in previous research. In a performance-based design approach, street geometrics and roadside elements are selected based on their influence on the desired driving speeds. The relationship between driving speeds and street features therefore needs to be determined. Although several studies have developed operating speed models for urban streets, all of these models were calibrated based on data for streets with speed limits of more than 30 km/h. The present research is designed to investigate the influence of various roadway and roadside characteristics on operating speeds on urban tangent street sections with a 30 km/h speed limit using profile-speed data. A simultaneous equation regression with a three-stage-least-square (3SLS) estimator was used for the modelling effort. The driving speed models developed in this study incorporate several street design factors, which provide helpful information for urban planners and street designers to cope with speeding issues on residential streets.     

Drivers' perceptions regarding speeding and driving on urban residential streets with a 30 km/h speed limit

Previous studies have shown very little information regarding drivers' opinions, attitudes and behaviours with respect to speeding and driving on urban residential streets with a 30 km/h speed limit. The present research aims to address this issue by conducting a questionnaire study with a sample of 367 Japanese drivers. The results showed that drivers tended to have positive beliefs about complying with the 30 km/h speed limit and understand the negative consequences of speeding; however, a majority of the drivers considered breaking the speed limit as a way to reduce their travel time. While the extent of speeding was found to be very serious, a number of drivers still supported the use of a 30 km/h speed limit on residential streets and favoured protecting the right of vulnerable street users. The logistic regression models developed in this study identified that the drivers who did not support the 30 km/h speed limit were associated with those who had committed traffic-law violations, who had negative beliefs about complying with the speed limit, who did not consider residents' opinions, who believed it is acceptable for them to drive at a high speed, and who felt it difficult to refrain from speeding. With regard to anti-speeding countermeasures, under drivers' point of view, streets should be designed to make the 30 km/h speed limit more credible, although this study also showed evidence supporting the application of public awareness programmes and social campaigns as speeding interventions. In addition, this research investigated drivers' speed choices in various specific driving circumstances, and six underlying factors affecting drivers' speed choices were determined. On the basic of the findings, the implications and suggestions for speeding interventions were also discussed.     

Intelligent speed adaptation: Preliminary results of on-road study in Penang,Malaysia

The first field experiment with intelligent speed adaptation (ISA) in Malaysia was held in December 2010 in the State of Penang. Eleven private cars were instrumented with an advisory system. The system used in the present study included a vocal warning message and a visual text message that is activated when the driver attempts to exceed the speed limit. When the driver decreases the speed, the warning stops; otherwise it is continuously repeated. The test drivers drove the vehicles for three months with the installed system, and the speed was continuously logged in all vehicles. The warning was however only activated in the second month of the three month period. The present study aimed to evaluate the effects of an advisory ISA on driving speed, traffic safety, and drivers' attitude, behavior, and acceptance of the system. To examine these effects, both the survey and the logged speed data were analyzed and explored. The results show a significant reduction in the mean, maximum and 85th percentile speed due to the use of the system. However, there was no long-lasting effect on the speed when the system was deactivated. In the post-trial survey, drivers declared that the system helped them well in following the speed limits and that it assisted them in driving more comfortably. Furthermore, the warning method was more accepted compared to a supportive system, such as active accelerator pedal (AAP). After the trial, most drivers were willing to keep an ISA system.     

Trip characteristics impact on the frequency of harsh events recorded via smartphone sensors

The Internet of Things (IoT) constantly offers new opportunities and features to monitor and analyze driver behavior through wide use of smartphones, effective data collection and Big Data analysis, resulting in assessment and improvement of driver behavior and safety. The objective of the present study is to investigate the impact of detailed trip characteristics on the frequency of harsh acceleration and harsh braking events through an innovative smartphone application developed within the framework of BeSmart project. A 200-driver naturalistic experiment spanning 12 months is carried out since July 2019. During the first two months, participants were asked to drive in the way they usually did, without receiving any feedback on their driving behavior from the application. Over the subsequent two months, participants were provided with personalized feedback, a trip list and a scorecard regarding their driving behavior, allowing them to identify their critical deficits or unsafe behaviors. Some of the most important risk factors, such as speed and driving above the speed limit, usage of mobile phone while driving and harsh events (acceleration and braking) are recorded through the application and subsequently analyzed. Generalized Linear Mixed-Effects Models were fitted to the trips of car drivers who made frequent trips for both experiment phases in order to model the frequencies of harsh events. Results indicate that maximum speed, the percentage of speeding duration and total trip duration are positively correlated with both harsh acceleration and harsh braking frequencies. On the other hand, the exposure metric of total trip distance was found to be negatively correlated with both harsh event types. A small positive correlation of the percentage of mobile use duration with harsh accelerations was also detected.     

基于驾驶安全舒适性的山区双车道速度限制研究

为综合考虑山区双车道行驶安全舒适性对速度的限制,基于交通安全工程理论,采用多元非线性数值回归分析技术,探讨了平曲线半径R、坡度i、坡长l与事故当量损失率P的相关关系及P、弯道速度V与心率增长率N的相关关系,建立了道路线形安全性评价模型和驾驶员行驶舒适性评价模型,并在对模型进行显著性检验及可靠性验证的基础上,推导限制安全舒适速度V。结果表明:在安全性最高的一般弯、坡路段阈值P=80、N=20%时,V=35 km/h达到最佳行驶安全舒适性;在安全性最低的急弯、陡坡路段阈值P=498、N=40%时,V=10 km/h为最大限制速度。     

Lane-following method for high speed autonomous vehicles

This paper presents a steering control method for lane-following in a vehicle using an image sensor. With each image frame acquired from the sensor, the steering control method determines target position and direction, and constructs a travel path from the current position to the target position either as an Arc-path or S-path. The steering angle is calculated from the travel path thus generated, and the vehicle follows the travel path via motor-control. The method was tested using a vehicle dubbed as KAV (Korea Autonomous Vehicle) along an expressway (Seoul Inner Beltway) trajectory with a variety of radii (50 m ∼ 300 m) while traveling at a speed of 60 km/h to 80 km/h. Compared with an experienced human driver, the method showed little much difference in performance in terms of lane-center deviation. The proposed method is currently employed for high speed autonomous driving as well as for stop and go traffic.     

车辆动荷载对水闸交通桥结构安全的影响

为了研究水闸与市政道路联合布置时,闸上交通桥车辆动荷载对水闸结构安全和交通安全的影响,以上海市奉贤区南门港水闸为研究对象,建立三维有限元模型,采用线性时程分析法计算了车辆动荷载下交通桥的应力分布。经计算分析,车辆动荷载产生的应力主要由交通桥主梁承担,对水闸主体结构应力影响不大,闸路结合的方案总体是合理的;在不同的车辆参数(标准车辆和吊车,车速分别为60 km/h、80 km/h、100 km/h)和不同车流量下,交通桥主梁跨中应力峰值均不相同,因此为提高水闸运行的安全性,应对过闸车辆限速限载。     

Motorcyclists' beliefs of compliance with the Malaysian school zone speed limit (SZSL)

Many road crashes that occur in school zones involve child pedestrians. Research has identified three contributing factors to road crashes, namely child behaviour, driver behaviour, and the environment. This study aims to identify critical beliefs that influence motorcyclist's intention to comply with the Malaysian school zone speed limit (SZSL). 159 Malaysian motorcyclists who have travel experience in school zones during school hours and non-school hours were recruited by using purposive sampling. Participants responded to a survey distributed by enumerators in public places and house-to-house survey conducted in Kedah, Malaysia. Step-by-step correlation and regression analysis were used to identify the motorcyclists' critical beliefs. The results identified that motorcyclists' beliefs of the community expectation for them to comply and that complying with the speed limit in school zones may reduce risk of crashes with school children were the critical beliefs. In addition, the observation of many motorcyclists in the school zone was also identified as critical beliefs influencing motorcyclists' intention to comply with the SZSL. The practical relevance of this study is to combine a public awareness campaign and safety education for the motorcyclists together with an enforcement method to reinforce motorcyclists' compliance with the SZSL. Additionally, to increase the awareness level among motorcyclists, traffic control devices, such as flashing lights and yellow lines could be implemented.     

公路施工区限速值大小研究

利用实地观测数据采用正交试验方法对施工区微观仿真模型进行了标定,接着对不同交通量与车辆组成条件下速度标准差随限速值的大小变化进行了仿真,并建立了两者之间的模型,研究表明施工区段相对上游非施工区段速度减小30 km/h能使速度标准差达到最小并能兼顾通行能力的要求。     

面向人因的车路协同系统综合测试及影响评估

面向冬奥主干通道兴延高速，以驾驶人适应性为导向，构建一种面向人因的车路协同系统硬件在环效能测试平台，针对多种道路条件、交通状态、特殊事件等面向高速公路设计13种交通情境，从主、客观2个维度实现车路协同系统包括主观感受、高效性、安全性、生态性、舒适性、有效性6个方面的驾驶人适应性评价，分析车路协同驾驶状态下的综合评估指标及影响机理。主观评估结果显示，车路协同技术对驾驶人有积极作用，52%的被试认为车载预警信息可以使行车过程更安全。客观运行结果表明：由于车路协同状态下驾驶人对于前方道路危险状况的可预知性，导致驾驶人提前降速，运行速度降低，效率有所下降；车路协同条件下的加速度和换道次数明显减小，其安全性显著提升；由于车路协同系统避免了驾驶人对于突发危险状况的紧急制动，因此车辆的油耗、排放均明显降低，其生态性改善效果显著；归因于驾驶人对于车路协同系统熟悉程度不足，导致舒适度各系统存在不一致的结论，也表明驾驶人对于车路协同系统的接受度和信任度均有待进一步提高；驾驶人在车路协同条件下可获取不同路段的限速值和超速提示，其有效性表现出明显的优势，速度跟随比有显著提升。所构建的测试平台和指标体系为进一步深层次挖掘车路协同的作用机理奠定了基础。     

基于驾驶员信息处理能力的高速公路作业区限速值计算方法

基于人体工程学原理,将驾驶员在高速公路作业区行驶过程中接触的交通信息分为道路几何信息、道路交通运行信息、交通管理控制信息、气候与环境信息及驾驶员自身信息,将作业区各种道路交通信息进行量化处理,在系统分析驾驶员对信息处理模式的基础上,提出了基于驾驶员信息处理能力的高速公路作业区车速速度限制值计算模型。以2006年5月哈大公路入口作业区为例,考虑车道宽度、开放车道数、隔离设施、合流机会、合流冲突及大车影响对驾驶员接受信息的量化影响,计算得出该作业区的限速值为50 km/h,与工程实际中采用的55 km/h吻合较好,验证了本文所提方法的有效性,为高速公路交通管理部门确定车辆速度限制标准提供了一种参考方法。     

基于随机参数Logit模型的校车事故伤害严重程度分析

为深入分析安全因素对校车事故伤害严重程度的影响，探寻事故数据中未观察到的异质性，基于随机参数Logit模型从驾驶员、车辆、道路特征及环境4个方面构建校车事故伤害严重程度模型。结果表明:①涉事车辆数为2辆且对应参数服从正态分布时，不发生死亡受伤事故的概率为83.84%；②驾驶员年龄35~44岁、涉事车辆数为1辆时，死亡受伤事故概率均降低0.58%；③道路限速值为40~50 km/h时发生死亡受伤事故概率增加0.35%，道路限速值大于60 km/h时发生死亡受伤事故概率增加0.96%；④安全气囊状态打开，死亡受伤事故概率增加2.35%；⑤交通控制方式为车道标线时可能伤害事故概率增加1.85%，控制方式为中央分隔带时未受伤事故概率降低1.44%，死亡受伤事故发生概率却增加0.48%；⑥不安全时倒车转弯时发生可能伤害事故概率降低0.42%，分心驾驶、未按规定车道行驶、跟车太近和其他（饮酒）时未受伤事故概率分别增加1.36%，0.56%，0.39%和0.97%，可能受伤事故和死亡受伤事故发生概率却有所降低。      

平原地区公路穿村镇路段安全综合治理对策研究

针对目前平原地区公路穿村镇路段事故多发的现状,本文首先对事故数据进行统计处理与分析,在数据处理分析的基础上找寻事故原因。平原地区公路穿村镇路段发生事故的事故原因主要是车速过快,混合交通相互干扰,视距不良等。并针对这些事故原因提出综合治理对策,包括预先提示、速度控制、交通分离、交叉口处置以及宣传教育执法等方面。其中既包括了视错觉标线、减速丘、接入管理、路宅分家等一系列新技术的原理,设计方案及工程应用,也对限速标志、交叉口整治等传统技术措施针对穿村镇路段公路特点进行了进一步的完善。只有将各种措施综合应用,综合治理,才能够最大限度的提高平原地区公路穿村镇路段的安全水平。     

Stationar- und Ubergangsverhalten von Sattel- und Lasttugen bei der Kreisfahrt: Lineare Berechnungen

ABSTRACT

Steady and Transient Turning of Tractor-Semitrailer and Truck-Trailer Combinations: A Linear Analysis

A simplified analysis is made of the yaw stability and control of the two types of the commercial vehicle combinations (tractor-semitrailer, truck-trailer) at a constant forward velocity during steady and transient turning. The combined vehicle is treated as a linear dynamic system (Fig. 2). The steer angle at the front wheels of the tractor (or truck) and the steady-state responses if the road verhicle train (yaw rate, articulation angles and sideslip angle) are calculated (Equations 18 to 25). Exploratory calculations are performed to determine the influence of the cornering stiffness of the tires for the two types of the vehicle combinations upon the steady-state responses (Figs. 7 to 10). For a linear simplified model of articulated vehicle the steady-state turning behaviour is stable also under conditions of rather high driving speed (70 km/h). A simplified analysis of the transient turning behaviour of the two types of road trains has shown the tractor-semitrailer to preserve stability even under driving speeds exceeding 70 km/h (Fig. 13), whereas the truck-trailer combinations appear to become oscillatory unstable if the driving speed rises above the 60 km/h margin (Fig. 14).     

On-road chasing measurement of exhaust particle emissions from diesel,CNG, LPG,and DME-fueled vehicles using a mobile emission laboratory

We designed and applied a mobile emission laboratory for on-road measurements of exhaust particles emitted from conventional diesel, compressed natural gas (CNG), liquefied petroleum gas (LPG), and dimethyl ether (DME)-fueled vehicles. Fuel type and vehicle driving conditions significantly affected the particle size distribution and the number concentrations of the nucleation mode. For all buses, the size distributions of particles in the exhaust under idling conditions had larger mode diameters than at constant speed conditions of 50 km/h or 80 km/h. The nucleation mode (< 50 nm) fraction of diesel, CNG, LPG, and DME at a constant speed of 50 km/h was 53%, 63%, 79%, and 99%, respectively, indicating that the DME-fueled bus emitted the most nanoparticles. As the vehicle speed increased from 50 km/h to 80 km/h, the nucleation mode fraction of diesel, CNG, LPG, and DME changed to 43%, 99%, 99%, and 99%, representing a significant increase in the number concentrations of nanoparticles in the CNG and LPG-fueled vehicles. The particle size distributions in the exhaust of diesel, CNG, LPG, and DME-fueled vehicles were not affected by increase in the chasing distance.     

32 m超低高度混凝土T梁动力性能试验与分析

为了研究开行120km/h货车后既有铁路32m超低高度混凝土T梁的运营状况、安全性和加固对策,选取1孔32m超低高度混凝土T梁进行自振频率、挠度、振幅等主要动力性能测试。结果发现跨中横向振幅超过限值,不能满足120km/h货车运行,需要提高该梁的竖向和横向刚度。     

Traffic calming measures: An evaluation of four low-cost TCMs' effect on driving speed and lateral distance

The transition from rural highways that afford higher speeds, to urban communities with lower speed limits and wide ranges of road users is a critical safety issue in Northern Iran that such transitions are frequent along a high-way running approximately parallel to the Caspian Sea shoreline and linking >50 urban communities. This study aims to investigate the efficiency of 4 low-cost traffic calming measurements (TCM) at a simulated 1.5 km length of this rural highway as a representative. 39 participants with at least 3 years of driving experience took part in this study, and comparisons of driver behaviors in case of speed and lateral position as a safety index in 4 scenarios and base scenario were outputted. MANOVA analysis was conducted on speed and lateral position data outputted from the simulator device, at the entry into the urban community. Comparison of mean speed results obtained revealed that all 4 treatments significantly reduced the mean speed of drivers. In this respect, the benefits of modified road signs were proven to be as successful as road surface markings. As another criterion for safety, the investigation showed road signs and transverse rumble strips increased lateral position, but the pattern of peripheral hatched markings significantly reduced the lateral position. In case of speed reduction, maintaining the reduced speed is another issue that has been resulted that as soon as TCMs end up, the speed increases, however, does not reach the former values.     

Stationar- und Ubergangsverhalten von Sattel- und Lasttugen bei der Kreisfahrt: Lineare Berechnungen

Steady and Transient Turning of Tractor-Semitrailer and Truck-Trailer Combinations: A Linear Analysis

A simplified analysis is made of the yaw stability and control of the two types of the commercial vehicle combinations (tractor-semitrailer, truck-trailer) at a constant forward velocity during steady and transient turning. The combined vehicle is treated as a linear dynamic system (Fig. 2). The steer angle at the front wheels of the tractor (or truck) and the steady-state responses if the road verhicle train (yaw rate, articulation angles and sideslip angle) are calculated (Equations 18 to 25). Exploratory calculations are performed to determine the influence of the cornering stiffness of the tires for the two types of the vehicle combinations upon the steady-state responses (Figs. 7 to 10). For a linear simplified model of articulated vehicle the steady-state turning behaviour is stable also under conditions of rather high driving speed (70 km/h). A simplified analysis of the transient turning behaviour of the two types of road trains has shown the tractor-semitrailer to preserve stability even under driving speeds exceeding 70 km/h (Fig. 13), whereas the truck-trailer combinations appear to become oscillatory unstable if the driving speed rises above the 60 km/h margin (Fig. 14).