Impact of Hydraulic System Stiffness on Its Energy Losses and Its Efficiency in Positioning Mechanical Systems

Hydraulic steering systems for mechanical devices, for example, manipulators or vehicle steering systems, should be able to achieve high positioning precision with high energy efficiency. However, this condition is very often not met in practical applications. This is usually due to the stiffness of the hydraulic system being too low. As a result, additional corrections are required to achieve the required positioning precision. Unfortunately, this means additional energy losses in the hydraulic control system. In this study, this problem is presented using the example of a hydraulic steering system for an articulated frame steer vehicle. This hydraulic steering system should provide the required directional stability for road traffic safety reasons. So far, this issue, connected mainly with the harmful phenomenon of so-called vehicle snaking behaviour, has not been solved sufficiently practically. To meet the needs of industrial practice, taking into account the current global state of knowledge and technology, Wrocław University of Science and Technology is performing comprehensive experimental and computational studies on the snaking behaviour of an articulated frame steer wheeled commercial vehicle. The results of these tests and analyses showed that the main cause of problems that lead to the snaking behaviour of this vehicle class is the effective torsional stiffness of the hydraulic steering system. For this reason, a novel mathematical model of the effective torsional stiffness was developed and validated. This model comprehensively took into account all important mechanical and hydraulic factors that affect the stiffness of a hydraulic system, resulting in the examined snaking behaviour. Because of this, it is possible at the design stage to select the optimal parameters of the hydraulic steering system to minimise any adverse influence on the snaking behaviour of articulated frame steer wheeled vehicles. This leads to minimising the number of required corrections and minimising energy losses in this hydraulic steering system. The innovative model presented in the article can be used to optimise positioning accuracy, for example, in manipulators and any mechanical system with hydraulic steering of any system of any mechanical parts.

Equipment Condition for Zebra Crossing Night-Time Safety Performance in Latvia

According to road traffic accident (hereinafter referred to as RTA) statistics, the vulnerable road users are pedestrians in Latvia. The aim of this study is to investigate and analyse technical equipment used on non-signalled pedestrian crossings (zebra crossings) in Latvia and to make suggestions for measures that would increase road traffic safety on zebra crossings. RTAs involving collisions with pedestrians were filtered from the Ministry of the Interior database for a three-year period from 2016 to 2018. Thirty-two zebra crossings with a higher number of accidents with pedestrians were observed on the spot during the daylight and at night in several cities of Latvia. The main emphasis during the observation was placed on traffic signs and zebra road marking performance. Pedestrian crossings were observed from car driver’s view by taking photographs during day-time and night-time observations. Most attention was paid to road sign and road marking visibility from driver’s seat position. Retroreflection coefficient R’ was measured for each pedestrian crossing road sign. It was found that the condition and performance of traffic organisation equipment were not maintained on a regular basis and the life cycle of some traffic signs had well expired. Many road signs do not comply with minimum requirements, and road markings have weak visibility during wet weather conditions. It is recommended to improve visibility of pedestrian crossings from driver’s view in the urban areas by increasing rain vision for road markings and higher retroreflection class for traffic signs.

Road Traffic Safety Development Trends in Latvia

The main focus of this article is on the road traffic safety development trends in Latvia. Soon after the regain of independence at the beginning of the 1990s, road traffic safety characteristics in Latvia were the worst in the Latvian history. The increase of car availability and affordability made the car a major road vehicle. The implementation of road safety programmes contributed to essential improvement of road traffic safety in Latvia. The number of road accident fatalities in 2020 compared to 1991 decreased more than sevenfold. Nevertheless, the current Latvian road traffic safety statistics is well below the average level of the EU member states and even the pandemics did not cause similar reduction as in most member states. This indicates that great improvement is still needed. The article shows the Latvian experience in road traffic safety enhancements and discusses the measures to improve road traffic safety.

A Spatial Autoregressive Quantile Regression to Examine Quantile Effects of Regional Factors on Crash Rates

Spatial autocorrelation and skewed distribution are the most frequent issues in crash rate modelling analysis. Previous studies commonly focus on the spatial autocorrelation between adjacent regions or the relationships between crash rate and potentially risky factors across different quantiles of crash rate distribution, but rarely both. To overcome the research gap, this study utilizes the spatial autoregressive quantile (SARQ) model to estimate how contributing factors influence the total and fatal-plus-injury crash rates and how modelling relationships change across the distribution of crash rates considering the effects of spatial autocorrelation. Three types of explanatory variables, i.e., demographic, traffic networks and volumes, and land-use patterns, were considered. Using data collected in New York City from 2017 to 2019, the results show that: (1) the SARQ model outperforms the traditional quantile regression model in prediction and fitting performance; (2) the effects of variables vary with the quantiles, mainly classifying three types: increasing, unchanged, and U-shaped; (3) at the high tail of crash rate distribution, the effects commonly have sudden increases/decrease. The findings are expected to provide strategies for reducing the crash rate and improving road traffic safety.

International legal and methodological support of road traffic safety: concepts and essential features

The article aims to learn about international legal and international methodological support of road traffic safety and transport operation. A number of statistical indicators, which testify to the catastrophic state of road traffic safety both in the world in general and in Ukraine in particular, are presented. The development of the definition of this concept is proposed to carry out in the classical way: by highlighting its corresponding essential features. These include: object, subject, system and purpose. The object is the sphere of road traffic of the motor transport specifically. The subjects are the international institutions (UN, WHO, World Bank, etc.) and international public associations. The system of such support is classified into eight main groups according to the sphere of regulation of the relevant legal relations within the general sector of road traffic safety. In turn, the international methodological support in this sphere is classified into seven types according to its focus. The main international conventions, resolutions and other decisions, first of all, the UN’s ones, and the international agreements forming the system of the international legal support of road traffic safety are presented. The purpose of this support is to increase road traffic safety around the world. Hence, the international legal and methodological support for road traffic safety is a set of regulations of an international nature, information materials issued with the participation of official institutions with international status, as well as international public associations aimed at ensuring traffic safety, reducing mortality and road traffic injuries in different countries of the world.

The system of international legal security of road-traffic safety

The article attempts to systematize international legal acts in the field of road-traffic safety. Its current state in the world is outlined. The general methodological bases of knowledge of a problem of the international legal security in the studied field are specified. Some components of the research methodology are directly identified in the system of international legal security in this area. Based upon the features of the system of legislation that takes place in the theory of law, a number of characteristic features of the system of international legal security of transport safety. This made it possible to offer an author's definition of this concept. The system of international legal security of road-traffic safety is represented by the classification of relevant international documents adopted during the last 70 years by the UN, WHO and other international institutions. Their division is carried out on the subject of legal regulation in the general field of road-traffic safety. This made it possible to identify eight groups of international legal acts: as for the formation of a global road-traffic safety policy; the creation of uniform traffic rules; in the field of passenger transportation and passenger transport; in the field of cargo transportation; in the field of accident prevention; in the field of road-traffic safety of youth; as for the road transport infrastructure; as for the punishment of persons for criminal offenses in the field of road-traffic safety and transport operation. Proposals are made for possible supplementation of the existing conventions taking into account the current state of development of the transport industry and the introduction of new technologies.

Prawo do życia i zdrowia a skuteczność kampanii społecznych na rzecz poprawy bezpieczeństwa ruchu drogowego w Polsce

Among many areas of human activity resulting in the development of civilization, it is possible to identify those significantly threatening his health and life. One of them is increasing mobility, that brings many benefits, but also lead to high social, economic and environmental costs of road traffic. According to the current data provided by World Health Organization, road accidents are listed as one of the ten leading causes of death in the world. In order to protect human life and health, international organisations, national gov- ernments, actors and organisations undertake a number of actions aimed at changing the behaviour of road traffic participants. Initiatives aimed at motivating road traffic participants to behave correctly include social campaigns. In Poland there are many social campaigns for the improvement of road traffic safety At the same time, it should be stressed that the preventive nature of this type of action makes it impossible to assess its effectiveness unequivocally. The article presents the results of direct studies on the recognition of social campaigns for the improvement of road safety in Poland and the assessment of their actual influence on the improvement of safety by road traffic participants.

Perception of Law Enforcement Officers on Preventing Road Traffic Injury in Vanuatu: A Qualitative Study

Background: Road Traffic Injuries (RTIs) cause approximately 1. 35 million deaths annually, and is the leading cause of death among people between ages 5 and 29. Law Enforcement Officers (LEOs) deal with Road Traffic Collisions (RTCs) and have contact with RTI victims at a daily basis, they possess an excellent perspective on preventing RTI. This study aimed to explore LEOs perceptions on risk factors and preventive measures of RTI in Vanuatu.Methods: This study employed qualitative methods that used Focus Group Discussions (FGDs) to gather data from 25 LEOs between October 14th and November 30th, 2020. Self-identified Ni-Vanuatu LEOs who have been serving for over 6 months and residing at the study setting were included in this study. Purposive sampling was used to recruit study participants from three municipalities in Vanuatu. A semi-structured open ended questionnaire was designed to guide the FGDs. Data obtained were sorted out using thematic analysis processed with some preconceived themes based on theory, and also allowing the data to determine new themes.Results: Data saturation was reached from conducting 5 FGDs with 25 LEOs who were traffic officers and municipal wardens. Five main themes and sixteen subthemes were generated from the study. The main themes include driving and alcohol, the challenges to effective enforcement, barriers to effective care and support for RTI victims, measures for road traffic control and promoting road traffic safety. The respondents perceived that addressing resources issues and the legislations on road traffic control act and vehicle regulation act will enhance prevention of RTI.Conclusion: This study explored the risk factors of RTI and the barriers to effectively prevent RTI in Vanuatu. The study also generated suggestions of a combination of road traffic control measures that could be implemented to prevent RTI. Future research should look at effective strategies of preventing RTIs in resource deficit settings.

Enhancing the Reliability of Communication between Vehicle and Everything (V2X) Based on Deep Learning for Providing Efficient Road Traffic Information

Developing efficient communication between vehicles and everything (V2X) is a challenging task, mainly due to the characteristics of vehicular networks, which include rapid topology changes, large-scale sizes, and frequent link disconnections. This article proposes a deep learning model to enhance V2X communication. Various channel conditions such as interference, channel noise, and path loss affect the communication between a vehicle (V) and everything (X). Thus, the proposed model aims to determine the required optimum interference power to enhance connectivity, comply with the quality of service (QoS) constraints, and improve the communication link reliability. The proposed model fulfills the best QoS in terms of four metrics, namely, achievable data rate (Rb), packet delivery ratio (PDR), packet loss rate (PLR), and average end-to-end delay (E2E). The factors to be considered are the distribution and density of vehicles, average length, and minimum safety distance between vehicles. A mathematical formulation of the optimum required interference power is presented to achieve the given objectives as a constrained optimization problem, and accordingly, the proposed deep learning model is trained. The obtained results show the ability of the proposed model to enhance the connectivity between V2X for improving road traffic information efficiency and increasing road traffic safety.

Research on Safety Evaluation of Commercial Vehicle Driving Behavior Based on Data Mining Technology

The arrival of big data era of internet of vehicles promotes the rapid development of logistics industry, which also indirectly leads to the high traffic accident rate, resulting in huge casualties and property losses. Driving behavior is considered the most central factor leading to traffic accidents. Therefore, a scientific and effective method for evaluating the safety of commercial vehicle driving behavior is urgently needed. In this study, a comprehensive evaluation model of driving behavior security based on multimembership function is proposed, and entropy weight method (EWM), analytic hierarchy process (AHP), and fuzzy comprehensive evaluation algorithm are integrated. Firstly, the evaluation system of commercial vehicle safety of driving behavior is established. Secondly, the weight vector of each evaluation index is determined by combining EW-AHP to eliminate the subjectivity of the traditional AHP algorithm. Then, the fuzzy comprehensive evaluation matrix is calculated based on the multimembership function and fuzzy mathematics theory, and the quantitative evaluation of driving behavior safety is realized based on the matrix. Finally, the real road vehicle driving data and driving behavior data are verified by experiments. The experimental results show that the model can accurately and reasonably evaluate the safety of driving behavior, which is of great significance to improve road traffic safety.