Introduction. Reducing vibration effects on machine operators is an urgent task; it allows to minimize the impact of vibrations on health, increase efficiency and attention. Accuracy and productivity can be improved. The problem of vibration protection is relevant for all types of machines, the working bodies of which interact with the soil and road surface. One of the impact reduction directions, along with vibration protection of cabs, is the development of vibration protection systems for operator seats. It is promising to use the effect of quasi-zero rigidity, which makes it possible to effectively damp low-frequency oscillations. For the proposed design based on a parallelogram mechanism, it is necessary to determine the condition for the horizontalness of the middle section of the static power characteristic.
Materials and Methods. For the developed design scheme, using well-known power static and geometric relationships, novel analytical relationships between the parameters of the initial data and the vertical lifting force of the mechanism were derived. The initial parameters include the linear dimensions of the mechanism, the size of the quasi-zero rigidity zone, the weight of the chair with the operator, and the spring stiffness. When deriving analytical dependencies, the coordinates of the points of the mechanism moving and stationary relative to their own base were used.
Results. The use of the developed analytical dependencies allows, for the given parameters of the initial data, to build a static power characteristic of the mechanism. The middle section of the characteristic is close to horizontal, but in general it is not horizontal. As an example, a static characteristic is given for a set of initial data values, the middle part of which is not horizontal. Equating the values of the vertical force of the mechanism at the left and right boundary points of the middle part of the characteristic made it possible to determine analytical dependences for ensuring quasi-zero rigidity.
Discussion and conclusions. The obtained analytical expressions for ensuring the horizontalness of the middle section of the static power characteristic were verified. Applying the derived conditions decreases the number of parameters in the original data by one. An increase in the two dimensional parameters of the mechanism significantly reduces the required rigidity of the mechanism spring, which reduces the metal consumption.

Introduction. A relevant objective of implementing the advanced systems of self-driving road construction vehicles can be accomplished by mathematical modelling. One of the important issues when creating a motion control system for a self-driving vehicle is to develop a trajectory following algorithm. The most well-known method of following the trajectory is a pure pursuit method, which is successfully used to control the movement of mobile robots.
Materials and methods. Hence, the research objective has been defined and is to adapt the pure pursuit method to control an autonomous grader. To achieve the research objective, the task of a mathematical model of the motor grader movement with front steering wheels has been developed, and a mathematical model of the motor grader motion control system has been compiled. Besides, we propose an integral criterion to evaluate the efficiency of the motion control system of a unmanned grader. Some theoretical studies of the mathematical model have been carried out and the dependencies of the integral criterion on the design and operational parameters of the grader, as well as on the parameter of the control method (visibility range) have been obtained. Moreover, the optimal values of the visibility range for various values of the base length, base coefficient and machine speed have been defined according to the proposed efficiency criterion.
Results. As a result of approximating the obtained optimal values, the pure pursuit method has been modified to control a self-driving motor grader, taking into account its design features and travel speed. The results obtained can be used to create the prototypes of unmanned control systems for road construction vehicles.

Introduction. The article is devoted to the results of a study of the cutting resistance of road asphalt concrete in the process of removing worn coatings by the working bodies of milling machines. The relevance of the work is due to the emergence of new grades of asphalt concrete and new types of cutting elements, for which it is difficult to predict the loads on the working body when solving the problems of designing new and justifying the operating modes of existing machines.
Purpose. To calculate the parameters of the working body of the road milling machine.
Materials and methods. The experimental work was carried out by determining the horizontal and vertical components of the resistance force of cutting asphalt concrete. The research was carried out on a mechanical stand with a movable plate, using recording equipment. Four different grades of asphalt concrete were destroyed. A twofactor experiment was conducted for each brand of material. The horizontal and vertical components of the cutting resistance forces were determined depending on the chip cross-sectional area, the grade of asphalt concrete and the type of cutting element.
Results. As a result of the experiment, data were obtained that make it possible to reasonably determine the loads on the working body of the road milling machine. It is proved that the dependence of the cutting resistance forces on the chip cross-sectional area of the cutting element has a nonlinear character. The data obtained allow to comprehensively answer questions concerning the justification of the parameters of road milling machines.
Discussion and conclusion. The obtained data allow to develop a mathematical model of the asphalt concrete milling process which will make possible to determine not only the loads on the working body and the energy intensity of the process, but also to reasonably approach the placement of cutting elements on the drum, determine the rational range of equipment operating modes and solve the problems of choosing operating modes depending on the type of asphalt concrete.

Introduction. To study the urbanized territory as a system, an approach was used that allows assessing gaseous and dispersed atmospheric pollution using a unified scale of environmental hazard. The features of air pollution in urban areas were considered, where a significant number of stationary and mobile sources of negative environmental impact are concentrated in limited overpopulated areas.
The purpose of the study. the use of theoretical foundations for a systematic assessment of the level of environmental hazard of an urbanized area under the influence of the road network due to a combination of gaseous and dispersed atmospheric pollution.
Methods and materials. Based on the improved model of the Urbanized Territory system, the following hypothesis is proposed: 1) motor traffic flows are both independent sources of formation of dispersed particles and sources of uplifting and spreading of particles, which in the presence of gaseous pollutants increases the level of environmental hazard of atmospheric pollution in an urbanized area; 2) atmospheric pollution of an urbanized area is formed when gaseous pollutants and dispersed particles from the street and road network are superimposed on the polluting background of other elements of the Urbanized territory system.
Results. The distribution maps of the calculated complex index of atmospheric pollution were obtained for the most problematic areas of the urbanized territory of Naberezhnye Chelny - Prospekt Mira and Kazansky Prospekt. The obtained results characterize the change in the level of environmental hazard of urbanized areas when gaseous pollutants and dispersed particles from the street and road network are superimposed on the polluting background of other elements of the Urbanized territory system.
Discussion and conclusion. Based on the generalization and comparison of the results of previous and current studies of the authors, comparing them with the results of other researchers, the hypothesis was fully confirmed. Conclusion. With the confirmation of the hypothesis, the goal of the study was achieved, which has scientific novelty and practical significance for the arrangement of a favorable and comfortable urban environment.

Introduction. This article is devoted to the problem of determining the territorial (pedestrian) accessibility of stopping points in large cities, which is one of the indicators of the quality of transport services for the population.
The aim of the study is to develop a methodology for determining the territorial (pedestrian) accessibility of stopping points of a large city with a thousand or more stopping points, based on publicly available data. The cause of the study was the dificulty of solving this problem, due to the large number of both stopping points and residential facilities, the straightforwardness of the shortest pedestrian approach, the lack of detailed instructions for performing calculations, etc. Based on the review of Russian and foreign scientific sources, approaches to determining the territorial accessibility of stopping points were considered, taking into account various additional parameters, such as the number of routes passing through a stopping point, the intensity of passenger exchange, the availability of socially significant objects, etc. The existing difficulties and peculiarities in determining the availability of stopping points for individual and multi-apartment residential buildings are given. In the framework of the System-wide measures for the development of road facilities federal project and the Safe and high-quality roads national project when preparing an application for the purchase of passenger transport rolling stock for Omsk, the authors carried out scientific and practical work, as a result, a methodology has been developed to overcome some difficulties in determining the transport accessibility of stopping points in a large city by using a partially automated approach at its individual stages.
Materials and methods. In particular, tools such as Yandex Map Designer, Table Excel Editor, Xtools Add-in for Excel, QGIS program, Macro in Excel using JavaScript API and HTTP geocoder were used.
Results. The calculation of territorial accessibility of stopping points using the developed methodology was carried out for Omsk. The application of this technique allows to reduce labour intensity of calculations up to 10 times. Discussion. The discussion of the results presented guidelines for further improvement of the developed methodology

Introduction. In the conditions of digitalization of the economy, the use of electronic document management in transport activities is of practical importance. Regulatory acts have established that the package of accompanying goods and transport documents for road transport includes the waybill of the car. In this regard, it is important to study the possibilities of an electronic waybill in the digital management system of a motor transport enterprise to increase the efficiency of its activities.
Materials and methods. The research uses methods of analysis and synthesis, digital modeling, methods of comparison and analysis of statistical data.
Results. Based on the system analysis of normative acts, the characteristic of the legal status of the waybill is given. A generalized scheme of information flows in the digital model of a motor transport enterprise has been formed, in which the waybill occupies a central place. The implementation of the Process Mining procedure in the information management system of a motor transport enterprise, created using the digital twins concept, made it possible to obtain quantitative characteristics of operations with waybills performed by the staff.
Discussion and conclusion. The results obtained have scientific novelty and are of practical interest for enterprises that own motor vehicles and carry out cargo transportation both for their own needs and on orders.

Introduction. Reducing the number of road traffic fatalities and aiming for zero deaths by 2030 is a key road safety government goal. The prevention of especially serious road accidents is one of the elements of achieving this goal. Analysis of the main factors contributing to the especially serious road accidents occurrence is the basis of an effective system for their prevention. A review of the scientific literature reveals a lack of knowledge in this area.

Materials and methods. The study was performed on the basis of especially serious road accidents sample. The accidents that occurred in the regions of the Siberian Federal District in the period from 2017 to 2020 were analyzed. The following parameters were analyzed: the number of dead and injured, the type of accident, the period of the day, the day of the week, the month of the year, the weather conditions and the condition of roadway. The study is based on a multidimensional frequency distribution. The calculations and graphs were made using MS Excel and Statistica.

Results. The results are presented using 2D and 3D histograms and cross tables. An analysis of the especially serious road accidents structure made it possible to distinguish two groups of accidents that differ in the number of the injured and dead. The influence of the analysed factors contributing to the especially serious road accidents occurrence is determined.

Practical importance. Knowledge of the factors influence on the frequency of especially serious road accidents occurrence will allow public services to effectively plan measures to prevent such accidents and respond to them. This will reduce the number of road accidents deaths.

Originality. Two groups of road accidents with especially serious consequences are identified and substantiated. It was found that the factors have different effects on the distribution of accidents in these groups. The study contains new knowledge of the factors contributing to the especially serious road accidents occurrence.

Introduction. The scheduling a transportation route of overweight and oversize goods by road is necessary to perform taken into account road traffic safety and security of artificial engineering structures (bridges, railway crossing and others). The monitoring and control of these procedures are performed by a licensing system in Russia. During the delivery a driver must carry out the transportation of such cargo within the approved route that is specified in a particular paper (authorization) located in the vehicle. Issues appear mostly during first shipment organization and when the route is outside the permanent vehicles location, when road network and bypass schemes are not familiar for the driver and the current GPS-systems bases do not include formal designations of roads according to state register. The authors suppose digital technologies implementation has to facilitate easier abnormal load shipments violations-free sufficiently.

The Materials and methods. A transportation organisation model of abnormal loads by BPMN notation has been developed. The key control points have been determined by the authors on the base of their own experience.

The results. An information model of forming and transmitting to the carrier authorization to transport abnormal load within the approved route has been developed. In the authorization the link to the cartographic resource is inserted in one of the QR-code field. Such approach makes possible to identify approved route clearly and unambiguously.

Uniqueness and practical meaning. The information model uniqueness consists of the transmission way of approves route to the customer – not the sequence of transit localities, but the cartographic resource. The practical implementation of such decision is addressed to help a carrier (a driver) to perform the abnormal load transportation strictly within the approved route.

Introduction. The article considers the possibility of forming a traffic optimization strategy based on a macroscopic fundamental diagram between urban areas. The zones of influence are constructed with the maximum and minimum values of border control, respectively, according to the category of different types of the zone of influence. The stability zones were formed by connecting the zones of influence and their shape changes with different values of exogenous flow and endogenous flow were analysed.

Materials and methods. The data on the traffic flow of the central part of the Jinan (PRC) road network are presented and an urban bizonal system is constructed using the obtained macroscopic fundamental diagrams. The modelling of the state of traffic flows was carried out and the regularity of their changes at different parameters of border control was obtained using the mathematical modelling MATLAB complex.

Results. As a result of the study, the traffic management solutions were obtained for the relatively parameter of completed and incomplete trips. The generalized options for optimizing traffic in the considered urban areas are proposed – four combinations of strategies for traffic management are performed serving the design optimization option with different traffic flow conditions.

Discussion and conclusions. For each multi-zone system of the road network, it is necessary to form its own characteristic variant of optimizing the traffic flow.

Introduction. The purpose of the article is to consider the effect of damping in the shock absorber on smooth running, continuous rolling of the wheel and energy loss in the suspension of the car.

Materials and methods. The review is based on the analysis of the amplitude-frequency characteristics of a two-mass car model and the dependence of the shock absorber operation during the oscillation cycle on the frequency of kinematic action.

Results. The article presents a calculation scheme and equations of dynamics of a two-mass oscillatory system equivalent to an automobile suspension. The frequencies at which the amplitude-frequency characteristics intersect for different levels of damping (invariant points) in a two-mass oscillatory system are calculated. The relative operation of the shock absorber for the oscillation cycle concept is proposed and a formula for calculating the relative operation of the shock absorber in a two-mass oscillatory system is given. A comparative analysis of graphs characterizing smooth running, continuous rolling of the wheel and energy losses in the suspension is carried out.

Discussion and conclusions. It is revealed that significant contradictions between these requirements arise only near the second resonance of the sprung mass, with an increase in the frequency of vibrations in the resonant zone, these contradictions are decrease.

Introduction. The accident rate in road transport in the summer period of the year in conditions of high ambient temperatures has a steady upward trend. The main reasons for this situation are changes in the condition of drivers and the low efficiency of the climate systems of some vehicles. Motor transport enterprises take into account the conditions of the external environment in their activities and adjust the technology of the transport process. Such environmental conditions are ice, fog, precipitation, low air temperature and others. However, high ambient temperature is not included in such a list. In this regard, the study of the features of the functioning of a motor transport enterprise in conditions of high ambient temperatures and the development on this basis of a functional model for ensuring road safety is an urgent task.

The purpose of this work is to improve the safety of road transport on the basis of the development of a functional structure of the road safety service of a motor transport enterprise, taking into account the high ambient temperature.

Methods. The work is based on the synthesis of general scientific research methods, which included the provisions of system analysis, as well as the provisions of the theory of transport processes, the technical operation of vehicles.

Results. The result of the work was the developed functional model of the road safety service of a motor transport enterprise, according to which the road safety service is endowed with control and administrative functions in relation to the activities of the personnel service, technical service and operation service on issues related to road safety. This model differs from the known ones in that it contains functions for responding to high ambient temperatures. An algorithm has been developed for the functioning of the traffic safety service in conditions of high ambient temperature, which prevents its influence on the increase in the aggressiveness of driving cars and the low efficiency of the climate systems of a part of vehicles. These provisions constitute the scientific novelty of the work.

Discussion and conclusion. The practical value of the work lies in the improvement of the tools of the motor transport enterprise, aimed at preventing an increase in the accident rate in conditions of high ambient temperatures.

Introduction. The results of the studies analysis on the protection of multi-storey buildings from progressive collapse are presented, which indicates insufficient attention to structural systems made of precast reinforced concrete, as a result of which design standards orient the designer to the use of not always effective monolithic structures. In particular, the problem of protection against progressive collapse with the exclusion of prefabricated crossbars of floors and coatings has not been practically studied. The purpose of the study is to develop a method for calculating a continuous system of hollow plates made by the method of formless molding.

Materials and methods. When designing the protection of multi-storey buildings from prefabricated elements, a static calculation is usually carried out with the exception of vertical structures (walls, columns) and the reinforcement of floor crossbars and coatings by ensuring their continuity. There are constructive methods of reinforcing prefabricated floors by creating continuous plates of adjacent spans with the help of connecting elements made of plastic reinforcing steel, but the calculation of such systems has not been developed. A method for calculating a system of two plates according to a rigid thread scheme is proposed.

Conclusions. Currently, theoretical methods have been developed to solve various problems of protecting buildings and structures from progressive collapse. However, there are many design requirements for the protection of multistorey buildings from progressive collapse, which have not yet received experimental and theoretical confirmation for the effective solution of practical problems. It seems that in this article one of these problems is partially solved.

Introduction. This paper presents the results of the assessment in-situ of the involvement of the concrete in the collapse of reinforced concrete buildings in Burundi.

Materials and Methods. The study consisted in the identification of the compressive strengths of the concrete structural elements of the reinforced concrete buildings under study. The compressive strengths were identified on the columns, beams and slabs using an industrial SCHMIDT 2000 sclerometer according to the protocol described in NF EN 12504-2(2003). Seventeen (17) three-storey buildings under construction were studied. For each building involved in the study, the reinforced concrete bearing elements of the first floor were studied. The results obtained were classified according to the cement grades (32.5) and (42.5) that were used in the studied buildings. A comparison of the compressive strengths obtained in-situ was established in relation to the normative values according to the cement grade used. The reliability of the obtained results was confirmed by the correlation between the results obtained in the laboratory conditions on the reinforced concrete experimental samples.

Results. This study showed that in Burundi up to 100% of collapses are caused by privately built structures. It was proved that the compressive strengths of 100% of the columns, 82% of the beams and 82% of the slabs that were made with a low-grade cement (32.5) had compressive strengths lower than the normative value (25MPa). In addition, the compressive strengths of 50% of the columns, 50% of the beams and 84% of the slabs made with a high-grade cement (42.5) were also proved to have compressive strengths lower than the normative values (35MPa).

Discussion and conclusion. In this study, the reliability of the results obtained by sclerometer test in-situ on the reinforced concrete buildings has been proved. Concrete has been shown to be a factor in the collapse of privately built reinforced concrete buildings in Burundi. Low-grade cement was observed to have a high impact in the collapse of reinforced concrete structures than the high-grade one. Therefore, as a recommendation, the process of building reinforced concrete buildings in Burundi needs to be regulated and controlled.