Safety performance functions for low-volume rural minor collector two-lane roadways

The Fixing America's Surface Transportation Act (FAST Act) highlights a data-driven method to improve traffic safety on all public paved roads in the U.S. The first edition of the Highway Safety Manual (HSM) is a widely used tool that provides crash predictive models in the form of safety performance functions (SPFs). There are no specific SPFs for low-volume roadways in the HSM. It is important to know that low-volume roadways are the major roadway types in terms of total mileage. This study used 2015–2019 crash data from Texas, incorporating with other relevant geometric and traffic variables, to develop SPFs for a specific low-volume roadway type (rural minor collector two-lane roadways). This study proposed a rules-based SPF developed approach that makes the prediction accuracies higher compared to the full model. The R² values range from 0.18 to 0.22 for all data (without splitting) for different injury level models. The prediction accuracies are improved in the decision tree-based models. For different class specific models (based on injury levels), the R² values range from 0.25 to 0.41. Three SPF groups are developed based on crash injury types. The SPFs can provide guidance in refining the prediction accuracies of rural minor collectors.     

The association between national culture,road safety performance and support for policy measures

There are considerable differences between countries when it comes to road safety performance, as indicated by the number of road fatalities per 100,000 inhabitants. These discrepancies are strongly associated with differences in wealth and prosperity, as expected, but are also related to national culture. The overall objective of this exploratory study is to identify relationships between national culture, road safety performance and public support for policy measures. Using the revised version of Hofstede's cultural dimensions, we show the strong correlation between national culture and road safety performance, which exists even after controlling for the national level of wealth as measured by the gross national income. Furthermore, by combining the national cultural dimensions with data on 29 countries from the second stage of ESRA, the E-Survey of Road users' Attitudes, this study demonstrates that culture also affects the level of public support for policy measures related to road safety. Specifically, for many measures, the degree of individualism accounts for a considerable part of the statistical variation in the public support for policy measures across countries—except for those measures for which the support is very high in most countries. Possible explanations are given for the seemingly paradoxical finding that countries which witness high resistance to road safety policy measures have nevertheless managed to achieve better road safety performance.     

大型客车被动安全性设计与对策

本文论述了大型客车被动安全性的重要性;分析了影响大客车被动安全性的因素;指出了提高大客车被动安全性应采取的一系列措施;提出了大客车被动安全性应达到的一些要求。     

临河地区农村客运安全监管存在的问题及应对措施

详细分析了内蒙古自治区临河地区农村客运存在的问题,并提出安全监管的应对措施。     

Decision fusion of a multi-sensing embedded system for occupant safety measures

The need for an embedded system that can fuse incomplete, inconsistent, and imprecise decisions from several sensing systems is a crucial step in achieving an effective decision for occupant safety measures. This paper deals with the decision fusion strategies of a multi-sensing embedded system to achieve significant enhancement in the reliability of occupant safety through the fused decisions. Multi-sensing approaches to determine weight, vision, and crash sensing are developed for occupant detection, classification, position calculation, and crash detection. A rule-based decision fusion algorithm is then developed to fuse the multi-sensing decisions. The developed sensing systems are incorporated into an embedded device. To execute the embedded system, a system interface between the software and hardware is developed using Lab Window/CVI with the C programming language. The experimental results demonstrated that the real time operation of the embedded system validate the effectiveness of the decision fusion algorithm, characterize the safety measures and monitor the decision application. Several events were tested that prove the performance of the embedded system is robust towards occupant safety measures.     

强化公交车辆技术安全防范措施，努力杜绝重大车辆事故

多年以来，北京公交集团始终坚持“安全第一，预防为主”的安全生产方针，在保证运营车辆安全运行方面采取了许多行之有效的车辆技术和安全管理措施。特别是在2008年北京奥运会期间，北京公交集团通过强有力的组织管理体系、优良的车辆技术配置、严密的技术保障手段，实现了全部奥运车辆安全运行、途中零故障的工作目标，受到各级领导、与会运动员和教练员、众多新闻媒体的广泛肯定和好评。     

Review of traffic safety evaluation at T-intersections using surrogate safety measures in developing countries context

In recent years, significant research has focused on traffic safety evaluations at unsignalized intersections due to complex and heterogeneous traffic movements as well as driver behaviour at such locations. However, at unsignalized T-intersections, priority traffic rules are less respected, which creates more conflicts. Further, multiple traffic movements such as right turns and through movements with varied driver behaviour results in increases the severity of conflicts. Many research studies have focused on the proactive safety measures in traffic safety evaluations as compared to crash-based analysis. Also, it is observed that Time to Collision (TTC) and Post Encroachment Time (PET) are the predominant types of surrogate safety measures in traffic safety evaluations. From the existing research outcomes, it is understood that these surrogate safety measures may give a better understanding of chain events for crash occurrences, collision mechanisms, and resulting consequences. However, further research is required in order to understand the suitability of such surrogate safety measures based on the complexity of heterogeneous traffic as well as driver behaviour with considerations of turning vehicles, particularly at T-intersections. In this context, this paper critically reviews the recent developments in Surrogate Safety Measures (SSM) and their applications at unsignalized intersections, with a particular focus on the T-intersection. This paper also brings attention to T-intersection safety evaluation with SSM in a developing country context. The outcome of the present study is more useful in the evaluation of traffic safety at T-intersections and suitable safety indicators for the evaluation.     

Assessment of the effectiveness of connected vehicle weather and work zone warnings in improving truck driver safety

Improving work zone safety remains a prime challenge for the transportation sector in the United States. In particular, the frequency and severity of work zone crashes involving large trucks in rural freeways are alarming. Lack of compliance with the instructions provided at work zones results in increased crash risk. In-vehicle advanced warning systems enabled by Connected Vehicle (CV) technology have the potential to prompt appropriate driver response, make navigation more predictable, and improve overall work zone safety. This study falls under the umbrella of the WYDOT Connected Vehicle Pilot Program and seeks to investigate the impacts of the Pilot's real-time weather and work zone notifications on the behavior of truck drivers in rural freeway work zone settings under poor visibility. Twenty professional truck drivers participated in this simulator study. The driving scenarios were designed to mimic the driving conditions experienced on Wyoming Interstate 80. Findings suggest that exposure to the CV notifications has promising safety benefits manifested in improved driver behavior and response. Furthermore, both the weather and work zone notifications acquired high approval from the participants in terms of usefulness and ease of understanding. Nonetheless, the display of multiple work zone warnings on the Human Machine Interface may had introduced little to moderate distraction for some participants. Overall, this study brings forth valuable lessons that are being funneled to support informed decision making to enhance the Pilot's existing Human Machine Interface design.     

Strategic planning support for road safety measures based on accident data mining

When actions and measures to increase road safety are to be planned by the police and local authorities, it is necessary to consider the specific accident circumstances as well as their historical, current, and predicted course. In particular, combinations of accident circumstances not contained in existing police statistics are often neglected, but may nevertheless be relevant, e. g., due to an increasing frequency. In order to identify these undiscovered interesting combinations, we propose a framework to support strategic planning of road safety measures based on several consecutive data mining stages. The scope, type, and location of road safety measures must be planned at a strategic level several months in advance to be fully effective. Therefore, it is essential to investigate and predict the accident circumstances and the temporal changes in their frequency comprehensively. Only with the knowledge, e. g., about the temporal pattern, locations, conditions of roads or speeds, meaningful actions can be derived. The embedded data mining approaches, i. e., frequent itemset mining, time series clustering, time series classification, forecasting, and scoring, are carefully selected, coordinated, and aligned. As a result, the framework provides police users with information about circumstances of accidents that are of interest in the future and presents their previous temporal and local patterns in a dashboard. In this study, the framework is applied in four different geographical regions. Thereby, default parameter settings for all approaches are found that are particularly suitable for the framework to investigate novel geographic regions.     

International and intercultural differences in arguments used against road safety policy measures

Policy measures in the field of road safety are not easily implemented for several reasons. Interventions can be undertaken in a multitude of policy areas, but it is often uncertain how effective the measures are. Moreover, policymakers may be reluctant to implement road safety policy measures because of the expected high costs and/or perceived low public support. To understand the arguments used against policy measures for road safety, a survey was conducted in ten countries (China, the United States, the United Kingdom, Belgium, Austria, Sweden, Greece, France, Nigeria, and Argentina). Respondents were presented with ten possible road safety measures and asked whether they would support or oppose them, what arguments their opinion was based on, and what the consequence of the measure would be on them individually. This paper describes the main findings of the research and then zooms in on three counterarguments: restriction of mobility, discrimination, and unjustifiability of state interventions, as well as on three of the measures considered—compulsory use of ISA systems, mandatory cycle helmets, and screening of older motorists. With this research, previous results on the level of public support have been confirmed, and new insights have been gained. If people feel safe when using a particular transport mode, they are less conscious of the need for additional or stricter measures affecting their transport mode. The perceived restriction of human liberties, fear of discrimination, and resistance to state interventions fuel opposition against measures. Moreover, people from different countries vary in what they consider fair and unfair, which is linked to the national culture and social organization. Even if a measure was perceived to be unfair from a certain perspective (e.g., discrimination), some respondents supported the measure. Our research also illustrates that even people who recognize that a measure would be effective might oppose it because they think it is not justified from at least one perspective, for instance, an excessive restriction of freedom.     

Study of the post-derailment safety measures on low-speed derailment tests

Prevention of train from derailment is the most important issue for the railway system. Keeping derailed vehicle close to the track centreline is beneficial to minimise the severe consequences associated with derailments. In this paper, the post-derailment safety measures are studied based on low-speed derailment tests. Post-derailment devices can prevent deviation of the train from the rail by catching the rail, and they are mounted under the axle box. Considering the different structures of vehicles, both trailer and motor vehicles are equipped with the safety device and then separately used in low-speed derailment tests. In derailment tests, two kinds of track, namely the CRTS-I slab ballastless track and the CRTS-II bi-block sleeper ballastless track, are adopted to investigate the effect of the track types on the derailment. In addition, the derailment speed and the weight of the derailed vehicle are also taken into account in derailment tests. The test results indicate that the post-derailment movement of the vehicle includes running and bounce. Reducing the derailment speed and increasing the weight of the head of the train are helpful to reduce the possibility for derailments. For the CRTS-I slab ballastless track, the safety device can prevent trailer vehicles from deviating from the track centreline. The gearbox plays an important role in controlling the lateral displacement of motor vehicle after a derailment while the safety device contributes less to keep derailed motor vehicles on the track centreline. The lateral distance between the safety device and rails should be larger than 181.5?mm for protecting the fasteners system. And for the CRTS-II bi-block sleeper ballastless track, it helps to decrease the post-derailment distance due to the longitudinal impacts with sleepers. It can also restrict the lateral movement of derailed vehicle due to the high shoulders. The results suggest that, CRTS-II bi-block sleeper ballastless track should be widely used in derailment prone areas.     

EC5000型电子调速器性能、使用及调整

介绍EC5000型电子调速器的系统性能、使用及调整方法。     

车用柴油机增压系统的发展——改善涡轮增压器与发动机的配合性能及发动机低速性能

近几十年来世界各国对增压技术的研究一直很重视,发展了许多新型增压系统。本文从提高增压发动机低速性能以及改善发动机与涡轮增压器的配合性能方面着手,简述当前国外最新增压系统的发展,并对各系统做一比较,探求其实用性及其发展潜力。     

高温季节下的车辆维护保养与安全行驶

高温季节下的车辆维护保养高温季节，车辆因充气系数下降、润滑油容易变质、机器零件易烧损。制动性能变差，驾驶员因高温易困、道路因行人增多、雨水打滑等原因易造成车辆受损，事故增多。如何做好夏季车辆的维护保养及高温下的驾驶员安全行车是一项十分重要的工作。     

高速公路特殊气象环境的管理

针对浓雾、沙尘、暴雨、大雪、强烈侧风等气象环境严重影响高速公路行驶车辆稳定性的问题,通过在特殊气象环境下对高速公路车辆行驶稳定性的各项影响因素的分析,得出了高速公路管理部门必需对气象条件、环境和道路条件进行实时检测,并且根据检测结果采取各种有效相应的措施.     

Optimisation of active suspension control inputs for improved performance of active safety systems

A collocation-type control variable optimisation method is used to investigate the extent to which the fully active suspension (FAS) can be applied to improve the vehicle electronic stability control (ESC) performance and reduce the braking distance. First, the optimisation approach is applied to the scenario of vehicle stabilisation during the sine-with-dwell manoeuvre. The results are used to provide insights into different FAS control mechanisms for vehicle performance improvements related to responsiveness and yaw rate error reduction indices. The FAS control performance is compared to performances of the standard ESC system, optimal active brake system and combined FAS and ESC configuration. Second, the optimisation approach is employed to the task of FAS-based braking distance reduction for straight-line vehicle motion. Here, the scenarios of uniform and longitudinally or laterally non-uniform tyre–road friction coefficient are considered. The influences of limited anti-lock braking system (ABS) actuator bandwidth and limit-cycle ABS behaviour are also analysed. The optimisation results indicate that the FAS can provide competitive stabilisation performance and improved agility when compared to the ESC system, and that it can reduce the braking distance by up to 5% for distinctively non-uniform friction conditions.     

级配碎石性能分析及在农村公路中的应用研究

从级配碎石材料的技术指标及稳定性指标分析入手,通过试验,得出级配碎石的冻融稳定性在试验后较试验前的CBR值、剪切强度、剪切模量虽呈下降趋势,但仍能满足农村公路对级配碎石的性能要求.     

成都市人民政府出台20条措施，进一步加强公交营运安全管理，加快公交事业发展

“6·5”公交车特大故意放火案给人民群众财产造成了重大损失，也使成都的城市形象蒙受了重大损失，引发了市民对政府一直以来“重视民生、改善民生、服务民生”决策部署所取得成绩的质疑。作为公交企业的主要负责人，心情仍然十分沉重，有责任对“6·5”事件进行认真思考和反思。同时，“6·5”事件对全国公交行业的影响也很大，现向各兄弟城市公交企业领导介绍成都市出台的20项措施，这些措施给出了对进一步加强公交营运安全管理、加快公交事业发展的具体办法。     

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.     

Age and road safety performance: Focusing on elderly and young drivers

The existing literature on young and elderly drivers indicates that they have the highest crash risks compared to other age groups of drivers. This study improves our understanding of the risk factors contributing to young and elderly drivers' elevated crash risk by examining self-report data from the E-Survey of Road User's Safety Attitudes (ESRA). The primary objective of this study is to compare the attitudes and behaviours of young, elderly, and middle-age drivers in Canada, the United States, and Europe. The main focus is on the practice of driving while distracted by mobile phones and driving while fatigued, as these are two dangerous behaviours that demonstrate the impact age may have. The analyses consistently showed that there are differences in the responses attributable to age. In all regions, drivers aged 18–21 years consistently reported higher rates of distracted and fatigued driving and higher rates of perceived social and personal acceptability of these behaviours than drivers aged 35–54 years. Elderly drivers aged 65+ years reported even lower rates of these behaviours and acceptability. Young drivers were also the least likely to believe that distraction and fatigue are frequent causes of road crashes, while elderly drivers were the most likely to believe this. This pattern with respect to age repeats in the support for policy measures as well; young drivers are least likely to support zero tolerance policies for mobile phone use when driving, while elderly drivers are the most likely to support this measure. Multivariate logistic regression modeling confirmed that elderly drivers were the least likely to engage in the use of mobile phones while driving or driving while fatigued. Statistically significant results showed that the middle-age group was less likely than young drivers to read a text message/email or check social media while driving and driving while fatigued.