Transport Technologies

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Increasing the complex intersections functioning efficiency by restriction of left-turn traffic flows
(Видавництво Львівської політехніки, 2020-02-26) Lobashov, Oleksii; Boikiv, Mykola; O. M. Beketov National University of Urban Economy in Kharkiv; Lviv Polytechnic National University
Providing rapid and safe traffic in cities requires the use of a set of planning and organizational measures. While the implementation of architectural-planning measures requires, except for significant investments, a quite long period, organizational measures can lead to a temporary but relatively rapid effect. For this purpose, an analysis of traffic flow metrics on the approaches to the intersection, traffic light cycle, and the traffic phasing is carried out. Conducted research indicates that left-turn flows cause significant delays and reduce traffic safety at the intersection. Therefore, increasing the efficiency of the crossroads needs redevelopment measures by restriction of the left-turn flows on the main road, change of the traffic flows phasing and optimizing the traffic light cycle. In the presence of adjacent intersections, the scheme of left turn realization is developed. The simulation of intersection functioning in existing conditions and under the change of left-turn flows movement organization is carried out in the PTV Vissim software environment. It is established that restriction of the left-turn flows at the controlled intersection allows to optimize the traffic light cycle and equip it so that the average delay for traffic flows will decrease in comparison with the current state.
Contents
(Видавництво Львівської політехніки, 2020-02-26)
Pedestrian and cyclist flows interaction in the urban street and road network
(Видавництво Львівської політехніки, 2020-02-26) Sotnikova, Anna; Francke, Angela; Lviv Polytechnic National University; Technische Universität Dresden
Due to the active popularization of sustainable urban mobility principles, there is an increase in the share of bicycle traffic in the overall modal split. The pedestrians are getting used to the fact that the cyclist is a full member of the traffic and has his/her own separate space. The concequence of this is cyclist and pedestrian flows conflicts. The article analyses the results of field research of cycling and pedestrian traffic volume. The permissible number of conflicts between them is defined, which makes it possible to understand the principles of combination or separation of flows in space. Based on the results obtained, recommendations for the design and arrangement of cycling and pedestrian infrastructure are provided.
To determination of traffic delay at controlled intersection
(Видавництво Львівської політехніки, 2020-02-26) Fornalchyk, Yevhen; Hilevych, Volodymyr; Lviv Polytechnic National University
Taking into account the importance of time spent on passing distances of vehicle routes that lie across city road network (RN), well-known approaches to the determination of vehicle delay in the movement process (waiting for passage and the passage) of controlled intersections are analyzed. Reasons that cause the growth of these delays and that have an impact on traffic light cycle duration are counted. At the same time, the authors justify the need for change in the existing term transport delay. It should be interpreted (concerning intersection passage) as a delay only in the case when the group of vehicles that have stopped before intersection could not pass this intersection during the permission signal and wait for the next such signal. If the vehicles in the first group could pass the intersection (possibly taking into account also waiting for the permission signal), then this is not a delay but the necessary component of the technological process of the route passage. From this point of view, an approach in the traffic delay determination method at controlled intersections is proposed taking into account the particular components of Webster`s formula and the volume-capacity ratio of RN that determine the motorization level of the city population. A comparison of the results of delay calculation, determined with the use of the proposed method and Webster’s formula, is carried out.
About passenger travels demand modeling in urban transportation systems
(Видавництво Львівської політехніки, 2020-02-26) Zhuk, Mykola; Pivtorak, Halyna; Lviv Polytechnic National University
In this paper, the basic concepts of modeling of urban transport systems are analyzed. The known variants of the definition of the concept of the transport system, its main components and the essence of the stages of identification of transport systems (TS) are presented. The example of the Lviv city TS shows the process of modeling the transport network, determining the time characteristics of the modeled transport system and forming a demand matrix for trips of a certain type in a certain segment of users (origin-destination matrix when moving students from their places of compact residence to the nodes of external transport for further implementation of intercity travel). The obtained indicators can be further applied in determining the demand for transportation in transport systems of large cities.
The impact of parameters of traffic flows of Lviv street-road network on the level of environmental and economic losses
(Видавництво Львівської політехніки, 2020-02-26) Kachmar, Roman; Lanets, Olena; Lviv Polytechnic National University
The analysis of directions and effectiveness of various methods of examining the impact of the urban street-road network on the level of eco-pollution was carried out with the use of the method of determining environmental and economic losses from changes in traffic flow indicators. The method of estimating the environmental damage dynamics due to harmful emissions of vehicles was applied. On the basis of conducted researches, practical recommendations were developed for such variants: prohibition of private transport motion on the road section, increasing the amount of electric transport, reducing the average age of vehicles to the accepted European level.
Changing of the bus driver`s functional state in city conditions
(Видавництво Львівської політехніки, 2020-02-26) Postranskyy, Taras; Vovk, Yuliya; Lviv Polytechnic National University
The functioning of a modern city is impossible without a proper mode of public transport and its network. Parameters of this transport system influence on the functionality of all supply chain links, training specialists, ensuring proper communication between parts of the city, the level of traffic safety, etc. At the same time, all these figures depend also on bus drivers and their work. This is due to the fact that this “human factor” influences on the proper functioning of the public transport system. It should be noted, that one of the indicators that allow analyzing the readiness of the driver to fulfill his direct professional duties is the functional state of his body. Analysis of this indicator allows creating appropriate recommendations for bus driver`s schedules of work and rest. According to this, managers can create such working conditions for drivers that will reduce the likelihood of erroneous actions. It will allow reducing the likelihood of road accidents. That`s why the importance of researching human as an operator in the transport process is increasing every year.
Change of drivers functional condition while moving along highways of different technical categories
(Видавництво Львівської політехніки, 2020-02-26) Krystopchuk, Mykhailo; National University of Water and Environmental Engineering
The article analyzes the influence of a human factor on road safety and the main methods of its research. The main indicators of the functional state of the drivers, which most accurately illustrate the change in the neuro-emotional stress while operating the vehicle in different road conditions, are determined. The regularities of changing the functional state of the drivers who were driving the vehicle along different categories of roads were established. It is revealed that the geometric features of the highway that determine its category have a significant impact on the performance of drivers, and, consequently, on the reliability of their work. The results of this research provide an opportunity to predict the functional state of the driver under different road conditions, as well as to adjust the routes of traffic of vehicles and the mode of work and rest of drivers.
Influence of transportation object position in car body on its vibrational loading
(Видавництво Львівської політехніки, 2020-02-26) Kindratskyy, Bohdan; Osmak, Oleksiy; Lviv Polytechnic National University
Dynamic model for research of object transportation location influence on its vibrating loading by moving through a number of single obstacles, road with random microprofile and rough road is offered. Differential equations and methods of their integration in MATLAB Simulink software product are presented. The values of frequencies and amplitudes of vertical oscillations, vibration acceleration of the transportation object at different locations in the vehicle body were obtained. It is found that the amplitude and maximum acceleration have the smallest values when the object is located in the center of gravity of the car, and the largest – above the rear axle (in the cargo compartment). Recommendations were to improve the vibration protection of the transportation object.
Justification of the criteria for allocation of separate lanes for urban public transport
(Видавництво Львівської політехніки, 2020-02-26) Royko, Yuriy; Bura, Romana; Rogalskyy, Roman; Lviv Polytechnic National University
The article is devoted to the methodology and research results of traffic flow parameters on the arterial streets, where different regimes of prioritizing urban public transport operate. The regularities of changes of such parameters make it possible to identify and differentiate the sections of transport network in terms of service efficiency, with the aim to implement various regulatory measures that would help to minimize delays in traffic flow. Quantitative and qualitative criteria for ensuring priority transit of urban public transport on different sections of transport network depending on the intensity, speed and composition of traffic, as well as the roadway parameters are defined and substantiated. According to the research outcomes, scientifically based approaches are recommended for the implementation of different schemes of traffic flows control on the sections of the transport network, which differ in planning parameters and of traffic conditions and provide rational transport service based on the criterion of time loss for movement of residents. These results are adequate for large and very large cities with dense construction area
Impact of street parking on delays and the average speed of traffic flow
(Видавництво Львівської політехніки, 2020-02-26) Hrytsun, Oleh; Lanets, Oleksii; Solodkyy, Serhiy; Lviv Polytechnic National University
The article is devoted to the problem of the impact of street parking on delays and the average speed of traffic flow. The sections with different ways of putting vehicles near the roadway in the central part of Lviv city with the most saturated flow were exposed to scientific scrutiny. For this purpose, the program software PTV Vissim is used. The causes of the impact of street parking on traffic flow speed and roadway capacity are analyzed. Simulation model was created, with the use of which the operation of the street section where parking is allowed and without parking, and also the impact of the parking duration on the average speed of traffic flow and its delays were investigated. It is clarified that the least values the average traffic delay has with the parking duration of 900 and 1800 sec, and the biggest values it has with the duration of 300 sec. It is determined that during the street parking design parallel to the sidewalk it is necessary to implement the restriction of the parking duration to increase the road network capacity and traffic flow speed.
Forecasting of urban buses dwelling time at stops
(Видавництво Львівської політехніки, 2020-09-14) Zhuk, Mykola; Kovalyshyn, Volodymyr; Hilevych, Volodymyr; Lviv Polytechnic National University
Intelligent Transport Systems in urban conditions is one of the solutions to reduce congestion of vehicles and the amount of harmful emissions. An important component of ITS is the assessment of the duration of a public transport trip. It is necessary to focus on the study of the duration of the bus (the duration of traffic between stops and the dwelling time). In this paper, the authors focused on determining the dependence of the duration of buses at stops depending on the demand of passengers. The dwelling time of buses at stops is not considered independent of the duration of the journey. The duration of the bus is the periods of time when the buses wait at the stops, and the travel time, which is the duration of the bus between each two stops. The study was conducted on the bus route #3A in Lviv. To determine the dwelling time of the bus at stops, it is necessary to take into account information about passengers and the trajectory of buses. The obtained data can increase the accuracy of forecasting in different traffic situations in comparison with the most modern methods.
Analysis of saturation flow on isolated lanes of controlled intersections with significant traffic intensity
(Видавництво Львівської політехніки, 2020-09-14) Murovanyi, Igor; Mazyliuk, Pavlo; Lutsk National Technical University
The methods and results of the investigation of intervals between vehicles during queue dissipation before controlled intersections with the further determination of saturation flow are reviewed in this paper. Having reviewed existing methods of determining the saturation in traffic flows, those are determined which provide the most certain results in conditions of intensive movement and take into account quite a large number of impact factors. Such methods are based on experimental measurement of intervals between vehicles during their passage through the stop-line in different directions of the controlled intersection. For the completeness of the analysis of such intervals, such factors are considered additionally as traffic composition and use of lanes by directions. Objects of the research are controlled intersections on approaches to which the slope is absent, there is no pedestrian and cyclist movement during the performance of turn, and conflicting traffic flows and also public transport stops in the zone of the intersection. The transitional research result is the determination of the number of vehicles that pass the stop-line during the permissive signal and time intervals between them, and the final result is the oncoming of saturation period on the lanes of straight and turns movement depending on traffic flow composition.
Contents
(Видавництво Львівської політехніки, 2020-09-14)
The road network traffic capacity taking into account public transport stops layout method
(Видавництво Львівської політехніки, 2020-09-14) Medvediev, Ievgen; Soroka, Sergiy; Volodymyr Dahl East Ukrainian National University
The vigorous motorization process is taking place in a growing number of countries year by year, and the number of people involved in road traffic is constantly increasing. The growth of the vehicle fleet and the volume of transportation lead to an increase in traffic that in the context of cities with a historical build-up leads to a traffic problem. It is particularly acute at the junctions of the road network. There is an increase in transport delays, queues, and congestion, causing reduce in speed, excessive fuel consumption, and increased wear-out of vehicle components and assemblies. These questions are constantly analyzed both in theoretical and practical terms. Today, the negative effects of motorization cannot be eliminated, and effective measures need to be developed to reduce their negative impact on the urban environment. An irrational location of public transport stops leads to a significant increase in transport delays. Respectively, the objective is to determine the optimal layout of the public transport stops on the street network, taking into account the existing and designed traffic conditions.
Authors
(Видавництво Львівської політехніки, 2020-09-14)
Vibration impact and noise protection devices with DVA for wheeled vehicles
(Видавництво Львівської політехніки, 2020-09-14) Diveev, Bogdan; Lviv Polytechnic National University
The article investigates vibration and noise protection devices for wheeled vehicles using dynamic vibration absorbers (DVA). Algorithms for modeling their dynamic characteristics based on adaptive calculation schemes are presented. A non-linear suspension with DVA and a noise-absorbing partition is considered, which is due to the introduction of a layered composite thinwalled structure with an intermediate damping layer with high damping properties and a DVA system, which provides better vibration and noise absorption. The problems of shock propagation during the overturn of the bus to passengers are also considered. The influence of the parameters of the shock absorber on the dynamic properties of the bus is investigated. The optimal parameters of the shock absorber are determined.
Change of car driver`s stress index during different periods of the day in urban traffic conditions
(Видавництво Львівської політехніки, 2020-09-14) Davidich, Yuri; Kush, Yevhen; Ponkratov, Denys; O. M. Beketov National University of Urban Economy in Kharkiv
Nowadays, the transport industry plays an important role in human well-being and the functioning of any settlement. Transport systems are involved in almost all areas of production and services. Therefore, any failure in its operation can lead to significant material costs. One of the most important such systems is “driver – vehicle – road – environment”. It should be noted, that the main link in it is “driver”. The correctness and duration of decision-making in different road situations depend on the driver`s functional state. This directly affects the level of traffic safety. Consequently, the tasks of modern transport research are the introduction of methods of the vehicle driver`s conditions monitoring and the detection of his fatigue in its early stages. That`s why the actuality of studying the human operator role in the transport process and the creation of modern means of driving assistance are increasing now.
Influence of public transport ergonomic features on passenger's functional state
(Видавництво Львівської політехніки, 2020-09-14) Afonin, Maksym; Lviv Polytechnic National University
The article means an analysis of the passenger transport services quality issue. Researches of public transport routes ergonomic features and their influence on a passenger functional condition are provided. The analysis of such indicators as cabin occupancy rate, noise level, vibration, and acceleration was carried out. Mathematical dependences of the passenger functional condition change considering vehicles ergonomic features were constructed. Threshold values of passenger compartment microclimate, providing the stress index normative values were determined. The most valuable result of the study is a comparative assessment of each type of public transport in terms of comfort and obtaining threshold values of noise, vibration, and acceleration which are acceptable for the normal passenger’s functional condition.
Analysis of demand for public transport service in Lviv city
(Видавництво Львівської політехніки, 2020-09-14) Gits, Ivanna; Zhuk, Mykola; Pivtorak, Halyna; Lviv Polytechnic National University
The demand for public transport on the example of Lviv city is analyzed in the paper. The aim of the trip, the duration of the trip, vehicle occupancy rate, walking approach to the stop, and the choice of public transport mode are determined as the main impact factors. The questioning of 1100 users of public transport is carried out. During the formation of transport strategy of public transport system functioning in large cities, it is necessary to consider such factors of functioning as optimal, from the view of transport provision, location of places of work and study, trips are up to 45 min; vehicle occupation rate is up to 80% (on the most routes); the walking distance is up to 600 m; vehicles of large capacity. The provision of these indicators in transport systems will provide an opportunity to increase the effectiveness and enlarge the demand for public transport services as a result of qualitative functioning.