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1

Impact of fog on dynamic parameters of vehicles in mixed traffic

Pandit Angshuman, Budhkar Anuj Kishor

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2025

|

z. 128

183--197

EN

The impact of fog on vehicle behavior under weak-lane discipline and heterogeneous traffic – typical of Indian highways – has not been adequately explored. This study investigates vehicle dynamics under varying fog densities (visibility range: 50–1000 meters). Real-time trajectory and visibility data were extracted by a novel image processing technique from highway video footage. The analysis reveals systematic adaptations in driver behavior: in shallow fog, longitudinal speeds increase, but in dense fog, drivers exhibit more abrupt longitudinal movements, with 85th percentile acceleration and braking reaching 4 m/s². However, lateral accelerations remain below 1 m/s². This suggests that in reduced visibility, perceptual uncertainties lead to risk-prone longitudinal movements, amplifying the potential for multi-vehicle collisions. The insights from this study are directly applicable to microscopic traffic simulation models, providing values of fog-induced acceleration, deceleration, and speed values for different scenarios. For practitioners and traffic operators, the findings underline the importance of visibility-aware interventions such as dynamic speed regulation, improved road-edge delineation, and vehicle-to-infrastructure (V2I) warnings. For drivers, the study offers evidence-based reasoning for cautious longitudinal driving and establishes the risks of overestimating visibility. Overall, this research bridges a critical gap in understanding fog-related traffic dynamics under complex driving conditions.

2

Design, development, and performance analysis of a magnetorheological damper for piping vibration control

Solepatil Sandesh, Mali Amol Shivaji, Dive Vikas Pralhad, Kolekar Aniket

Advances in Science and Technology. Research Journal

|

2025

|

Vol. 19, no. 5

344--355

EN

A magnetorheological (MR) damper is a type of smart device that utilizes magnetorheological fluids—fluids whose viscosity can be altered by an applied magnetic field. A simple design is provided by a Magnetorheological (MR) damper, which consists of MR fluid, magnetic coils, and a hydraulic cylinder. In addition to being easy to construct and controllable in the field, MR dampers have several other benefits, including a relatively low power input need, the capacity to generate high yield stress up to 100 kPa, and stable operation over a broad temperature range (-40ºC to 150ºC). while MR silencers are designed to function between -40ºC and 150°C, their effectiveness in specific scenarios may be influenced by additional factors beyond the operational limits of the MR fluid alone. MR fluids are also non-toxic and impervious to contaminants. The MR damper can operate as a traditional passive dashpot in fail-safe mode when there is no magnetic field. Due to these advantages, MR dampers are becoming increasingly popular in a variety of applications, such as knee prosthesis, big bridge vibration control, automotive suspensions, and seismic vibration mitigation. The performance of the developed damper is compared to a standard MR damper to determine the optimal blend for vibration attenuation Understanding the nonlinear hysteretic behavior of an MR damper is essential for effective control under an applied magnetic field. In present work Magnetorheological damper is designed, built, and tested for piping vibration having load carrying capacity of 1910N and its transmissibility for various blends of MR fluid with percentage 40% , 45% and 50% (by weight of oil in damper) is observed and corresponding transmissibility of damper is compared with Standard Magnetorheological damper.

3

Wpływ fotoradarów na prędkość jazdy pojazdów - część II

Klepacz Aneta, Bryniarska Zofia

Transport Miejski i Regionalny

|

2024

|

nr 4

3--10

PL

Artykuł ma na celu zweryfikowanie skuteczności stosowania fotoradarów i ich wpływ na prędkość samochodów osobowych i ciężarowych. Część I artykułu zawiera omówienie zachowań kierowców na drodze wraz ze sposobami radzenia sobie z wykroczeniami, a także przedstawia przyczyny wypadków drogowych na podstawie raportów policyjnych z 2022 roku. W części II zawarto analizę czynników wpływających na zwiększanie prędkości przez kierowców. W ramach metody badawczej przeprowadzono dwa pomiary dla dwóch różnych lokalizacji fotoradarów. Miejsca pomiarowe różniły się ukształtowaniem terenu i obowiązującym ograniczeniem prędkości. Znajdowały się na DK7 w miejscowości Jawornik i DK47 w miejscowości Nowy Targ. Dopuszczalna prędkość na badanych odcinkach to odpowiednio: 70 km/h i 50 km/h. Pomiary wykonano przy obecnym fotoradarze i tydzień po jego ściągnięciu. Fotoradary, na zlecenie Głównego Inspektoratu Transportu Drogowego, ściągano na czas serwisowania. Część II artykułu zawiera też porównanie wykroczeń powodowanych przez kierowców samochodów osobowych i ciężarowych, przy obecnym urządzeniu mierzącym prędkość, a także przy jego braku. Na podstawie Generalnego Pomiaru Ruchu przeprowadzonego w latach 2015 i 2020 dla obu lokalizacji fotoradarów oszacowana została średnia dzienna liczba wykroczeń.

EN

The article aims to verify the effectiveness of the use of photo radars and their impact on the speed of cars and trucks. Part I of the article (TMiR No. 3/2023) includes a discussion of drivers’ behaviour on the road along with ways to deal with violations, and presents the causes of road accidents based on police reports of 2022. Part II contains an analysis of the factors influencing drivers to increase their speed. As part of the research method, two measurements were carried out for two different speed camera locations. The measurement locations differed in terrain and the applicable speed limit. They were located on DK7 in Jawornik and DK47 in Nowy Targ. The permissible speed limits on the surveyed sections were respectively: 70 km/h and 50 km/h. Measurements were taken at the current speed camera and one week after it was taken down. The speed cameras were removed for servicing on the order of the Main Road Transport Inspectorate. Part II of the article also contains a comparison of violations caused by car and truck drivers, with and without the current speed measuring device. Based on the General Traffic Measurement carried out in 2015 and 2020, the average daily number of violations was estimated for both speed camera locations.

4

Wpływ fotoradarów na prędkość jazdy pojazdów - część 1

Klepacz Aneta, Bryniarska Zofia

Transport Miejski i Regionalny

|

2024

|

nr 3

17--25

EN

The article aims to verify the effectiveness of the use of photo radars and their impact on the speed of cars and trucks. It contains a discussion of drivers’ behaviour on the road along with ways to deal with offenses, as well as a presentation of the causes of road accidents based on police reports of 2022. The factors influencing drivers’ speeding are analysed. As part of the research method, two measurements were carried out for two different speed camera locations. The measurement sites differed in terrain and speed limits. They were located on the road No. DK7 in Jawornik and No. DK47 in Nowy Targ. The permissible speed on the tested sections is - respectively - 70 km/h and 50 km/h. The measurements were taken at the presence of the speed camera and one week after it was removed. The speed cameras were pulled down for servicing on behalf of the General Inspectorate of Road Transport. The article contains a comparison of offenses committed by drivers of passenger cars and trucks with and without a speed measuring device. Based on the General Traffic Measurement carried out in 2015 and 2020 for both speed camera locations, the average daily number of offenses was estimated.

PL

Artykuł ma na celu zweryfikowanie skuteczności stosowania fotoradarów i ich wpływ na prędkość samochodów osobowych i ciężarowych. Część I artykułu zawiera omówienie zachowań kierowców na drodze wraz ze sposobami radzenia sobie z wykroczeniami, a także przedstawia przyczyny wypadków drogowych na podstawie raportów policyjnych z 2022 roku. Analizie poddano czynniki wpływające na zwiększanie prędkości przez kierowców. W ramach metody badawczej przeprowadzono dwa pomiary dla dwóch różnych lokalizacji fotoradarów. Miejsca pomiarowe różniły się ukształtowaniem terenu i obowiązującym ograniczeniem prędkości. Znajdowały się na DK7 w miejscowości Jawornik i DK47 w miejscowości Nowy Targ. Dopuszczalna prędkość na badanych odcinkach to odpowiednio: 70 km/h i 50 km/h. Pomiary wykonano przy obecnym fotoradarze i tydzień po jego ściągnięciu. Fotoradary, na zlecenie Głównego Inspektoratu Transportu Drogowego, ściągano na czas serwisowania. Część II artykułu (TMiR nr 4/2024) zawiera porównanie wykroczeń powodowanych przez kierowców samochodów osobowych i ciężarowych, przy obecnym urządzeniu mierzącym prędkość, a także przy jego braku. Na podstawie Generalnego Pomiaru Ruchu przeprowadzonego w latach 2015 i 2020 dla obu lokalizacji fotoradarów oszacowana została średnia dzienna liczba wykroczeń.

5

Super seven “S” trends (SSST) that shape the future of Philippine global ports

Baylon A. M.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2024

|

Vol. 18 No. 1

161--167

EN

The paper presents the port investments and initiatives the Philippine Port Authority spearheaded, including financial performance and operational highlights. The extensive readings on the Philippine Port Authority (PPA) report, online searches, documentary analysis, observations from the press, etc., and interviews were evaluated and divided into Seven Super "S" Trends (SSS-T). This 7S-T includes STEMS, SIZE or SCALE, SPEED, SMARTNESS, SUSTAINABILITY, SAFETY and SECURITY, SCARCITY, and SUPPLY, which together would influence the future of global ports. These "S" Trends will be explained in light of current (2017–2018) projects, trends, best practices, and port investments that are being started and carried out in the Philippines despite obstacles and difficulties. The paper concludes with a few closing thoughts. The views and analysis set out in this paper are those of the author(s) and not the official viewpoint of the Philippine Port Authority (PPA) unless otherwise the statement(s) of the person(s) have been quoted "in toto." The analyses provided in this paper are ideas and interpretations of the author(s) as maritime educators and researchers and are solely intended for academic discourse. Although the Seven Super Trends (SST) may use different terms, they may represent the same trends seen by port specialists because trends in ports are a global concern.

6

Proactive safety assessment of urban through-roads based on GPS data

Ambros Jiří, Elgner Jan, Valentova Veronika, Bąk Radosław, Kieć Mariusz

Archives of Transport

|

2024

|

Vol. 69, iss. 1

113--125

EN

Road safety is a worldwide issue, while urban roads account for a high share of serious road injuries, especially involving vulnerable road users, such as pedestrians or cyclists. Specifically, the safety of major roads through built up areas (through-roads) is insufficient due to mixed traffic conditions including vulnerable road users, varying driving behaviour, and many disruptions, which are combined with excessive speed. In this context, various traffic calming measures have been implemented to improve road safety, such as gateways or pedestrian refuge islands. However, the specific safety impacts of traffic calming combined with specific characteristics of through-roads are often unknown, since most traditional evaluations have been limited by small sample sizes of crash data, as well as wide variations in physical and road characteristics. To overcome the limitations of crash-based evaluations, we used the GPS-based data from a sample of 21 Czech and 12 Polish through-roads to develop the Speed-Safety Index, which combines speed, speed variance, and traffic volume. Our study has three novelty features: (1) To assess safety, we used speed and speed variance simultaneously. (2) To complete the missing link between specific traffic calming measures and safety, we validated the statistical relationship between the developed Speed-Safety Index and crash history. (3) To prove the usefulness of the developed index, we also showed its practical interpretation by proving the effect of spacing between traffic calming measures on safety. The index proved to be well correlated to crash frequency and it also proved the effect of spacing between traffic calming measures: the longer spacing, the smaller speed-reducing effect. The paper concludes with a discussion on the limitations, which we plan to address in further research, by moving from the current macro-perspective (Speed-Safety Index on the level of through-roads) to the micro-perspective (focusing on individual directions, locations, and traffic calming measures). We also plan to investigate the method’s applicability in different contexts. If the approach proves feasible, with reliable and valid results, it may become an alternative for a proactive network-wide road assessment, as called for by the European Road Infrastructure Safety Management Directive.

7

Development o the Design of an Experimental Adsorber and Optimization of its Gas-Dynamic Parameters

Mykhailiuk Vasyl, Dzienniak Damian, Kryzhanivskyy Yevstakhiy, Deineha Ruslan, Stetsiuk Roman, Uhryński Andrzej, Rokita Tomasz

Advances in Science and Technology. Research Journal

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2024

|

Vol. 18, no. 6

177--188

EN

Various technologies and equipment are used to reduce greenhouse gas emissions. For example, the method of adsorption is used to capture carbon dioxide (CO2) from the smoke emissions of cement industries. In the adsorption process using zeolites, devices such as adsorbers are typically employed. Zeolites, a versatile group of aluminosilicate materials, are known for their high surface area and selective adsorption properties, making them effective for CO2 capture. The effectiveness of the adsorber depends on many factors, including its geometric dimensions and shape. Adsorbers with a central inlet flow have uneven gas distribution at the entrance to the adsorbent layer, which reduces their operational efficiency. To eliminate this disadvantage, various devices installed at the output of the adsorber inlet are usually used. Analysis of such devices shows that they do not provide maximum adsorption efficiency. To study the efficiency of zeolite operation for capturing carbon dioxide contained in the smoke gases of cement industries, the design of a laboratory adsorber is proposed featuring a cyclone and distribution device in its lower part. The cyclone prevents the adsorbent from being contaminated by drip fluid, which reduces the efficiency of the adsorption process in the gas, and the distribution device reduces the uniformity of gas distribution at the entrance to the adsorbent layer. This paper proposes a computational fluid dynamics (CFD) model and design of the distribution device, which was analyzed and modified to significantly increase the uniform distribution of gas at the entrance to the adsorbent layer. Compared with other designs of distribution devices, the proposed design is simpler and performs better under varying gas flow rates.

8

Kinematic synergy of speed reduction during stair descent

Nakamura Jun, Igura Reo, Anan Masaya

Acta of Bioengineering and Biomechanics

|

2024

|

Vol. 26, no. 2

154--158

EN

This study aimed to quantify multi-segmental coordination using Uncontrolled Manifold (UCM) analysis to examine the effect of speed reduction on the control of stair descent. Methods: Twenty healthy participants performed stair descent at a self-comfortable pace for normal speed conditions and at a slow speed set to a metronome rhythm of 60 beats/min. UCM analysis was separately conducted for the center of mass (COM) and swing foot, with anteroposterior and vertical movements designated as task variables, and segment angles defined as elemental variables. ΔV, the normalized difference between the variance in segment angle that does not affect task performance (VUCM) and the variance that does affect task performance (VORT) was calculated separately for the COM and swing foot and compared between normal and slow speeds. Results: The VORT for the COM and the swing foot in the anteroposterior direction were significantly lower at slow speeds than at normal speeds. The VORT of task-relevant segment angles affecting COM control in the vertical direction was significantly higher at slow speed compared to normal speed. Additionally, the ΔV in segment angle variance impacting swing foot control in the anteroposterior direction was significantly greater at slow speed than at normal speed. Conclusions: The findings suggest that descending stairs at reduced speed promotes enhanced coordination of lower limb segments for controlling the swing foot in the anteroposterior direction, while concurrently increasing segmental variability that destabilizes the vertical COM.

9

Zderzenie szynobusu z zespołem pojazdów. Zabrakło jednej sekundy…

Młodożeniec Marek

Paragraf na Drodze

|

2023

|

Nr 2

81--89

PL

W artykule omówiono przypadek zderzenia szynobusu z naczepą. Wskazano przyczynę zderzenia i wpływ przekroczenia dopuszczalnej prędkości przez prowadzącego szynobus na zaistnienie wypadku. Na zakończenie zwrócono uwagę, że do zapobieżenia tego typu zdarzeniom bardzo często wystarczające jest stosowanie się do przepisów art. 25 ust. 2 oraz art. 28 ust. 1 i 2 ustawy Prawo o ruchu drogowym.

EN

A case of railbus – semitrailer collision is discussed. The cause of the collision and the influence of the railbus driver exceeding the permissible speed on the occurrence of the accident are indicated. In conclusion it is emphasized that this type of accidents can very frequently be prevented by conforming to the regulations of art. 25 para. 2 and art. 28 para. 1 and 2 of the Road Traffic Act.

10

Ustalenie rzeczywistej prędkości tramwaju na podstawie wartości zarejestrowanych przez rejestrator ATM

Dąbkowski Paweł Grzegorz, Dylewski Sławomir

Paragraf na Drodze

|

2023

|

Nr 2

65--79

PL

Celem artykułu jest przedstawienie różnic pomiędzy prędkościami tramwaju zapisanymi w rejestratorze pojazdu a zmierzonymi urządzeniem pomiarowym i wprowadzenia propozycji zastosowania współczynnika korekcyjnego w celu ustalenia rzeczywistej prędkości tramwaju. W czasie eksperymentu realizowanego do jednej z opiniowanych spraw stwierdzono różnice pomiędzy wartościami prędkości zapisanymi w rejestratorze ATM i zmierzonymi urządzeniem VBOX Sport. Zauważono również, że już w rejestratorze zapisane są cztery prędkości, których wartości nie są takie same. W artykule przedstawiono źródła tych prędkości i obliczono współczynnik, który posłużył do odtworzenia rzeczywistych prędkości i przyspieszeń zarejestrowanych w czasie rzeczywistego zdarzenia.

EN

The aim of the article is to present the differences between the tram speeds recorded in the recorder and those measured with a measuring device, and to propose the use of a correlation coefficient to determine the real speed. During the experiment, performed for an expert witness opinion, differences were found between the speed values recorded in the ATM recorder and those measured with the VBOX Sport device. It was also noticed that four speeds of different values had already been recorded in the recorder. The sources of these speeds are presented and the correlation coefficient between the measured and recorded values, which was used to reproduce the actual speeds and accelerations recorded during the real event, is calculated.

11

Frictional Aspects of Operation for Centrifugal Accelerators with Radial Blades

Krupicz Bazyli, Barsukov Vladimir G., Ilkevich Maria A.

Tribologia

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2022

|

nr 3

39--48

EN

The work aims to determine the friction effect and change the velocity and kinetic energy during the movement of solid particles along the rotating machine's radial blade surface. It has been previously shown that the influence of the frictional forces of the particle against the rotor disc is negligible compared to the influence of the centrifugal force and the friction force of the particle against the rotor blade. Based on the analysis of the differential equation solution for particle motion along the surface of the blades, it was established that the total sliding velocity of a particle increase intensively in the initial period of motion and approaches asymptotically to the values described by a linear function, practically independent of the initial position of the particle. The obtained analytical expressions enable the determination of change in the relative and total velocity of the particle, the angle between the respective velocity vectors and its kinetic energy. Changes in the values of these parameters were also estimated for a wide range of variability of the friction coefficient.

PL

Celem pracy jest określenie wpływu tarcia cząstek stałych na ich prędkość i straty energii kinetycznej podczas ruchu po powierzchni łopatek promieniowych maszyn wirnikowych. Wykazano, że wpływ sił tarcia cząstki o tarczę wirnika jest pomijalnie mały w porównaniu z wpływem siły odśrodkowej i siły tarcia cząstki o łopatkę wirnika. Na podstawie analizy rozwiązania równania różniczkowego ruchu cząstek po powierzchni łopatek ustalono, że całkowita prędkość poślizgu cząstki intensywnie wzrasta w początkowym okresie ruchu i zbliża się asymptotycznie do wartości opisanych funkcją liniową, praktycznie niezależną od położenia początkowego cząstki. Uzyskane wyrażenia analityczne umożliwiają określenie: zmiany prędkości względnej i całkowitej cząstki, kąta pomiędzy odpowiednimi wektorami prędkości oraz jej energii kinetycznej. Dokonano również oszacowania zmiany wartości tych parametrów dla szerokiego zakresu zmienności współczynnika tarcia.

12

Obowiązki kierujących pojazdami i pieszych przechodzących przez przejście dla pieszych po nowelizacji ustawy Prawo o ruchu drogowym

Stefański Ryszard A.

Paragraf na Drodze

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2022

|

Nr 1

7--19

PL

Przedmiotem artykułu jest analiza zmian dotyczących przechodzenia pieszego po przejściu dla pieszych, wprowadzonych ustawą z dnia z dnia 25 lutego 2021 r. o zmianie ustawy Prawo o ruchu drogowym. Jego celem jest wykładnia użytego w art. 13 ust. 1a ustawy Prawo o ruchu drogowym (dalej p.r.d.) pojęcia pieszy wchodzący na przejście dla pieszych, a także jego obowiązków w postaci zachowania szczególnej ostrożności, niewchodzenia na jezdnię bezpośrednio przed jadący pojazd oraz niekorzystania z telefonu lub innego urządzenia elektronicznego. Rozważania zmierzały także do wyjaśnienia pozostających w związku z uprawnieniem pieszego obowiązków kierującego pojazdem zbliżającego się do przejścia dla pieszych polegających na zmniejszeniu prędkości tak, aby nie narazić na niebezpieczeństwo pieszego znajdującego się na tym przejściu albo na nie wchodzącego oraz ustąpieniu pierwszeństwa pieszemu wchodzącemu na to przejście. Dla osiągnięcia tych celów zostały wykorzystane takie metody badawcze jak analiza tekstu normatywnego, metoda językowa i logiczna. Artykuł ma znaczenie - ze względu na wyjaśnienie kontrowersji jakie rodzi art. 13 ust. 1a p.r.d. - przede wszystkim dla biegłych z zakresu ruchu drogowego oraz kierowców i pieszych.

EN

The subject of the article is an analysis of the amendments regarding a pedestrian walking across pedestrian crossing, introduced by the Act of February 25, 2021 amending the Act on Road Traffic. Its aim is to interpret the concept, provided in Article 13 (1a) of the Act on Road Traffic, of a pedestrian entering a pedestrian crossing as well as his/her duty to exercise special care, not to enter the road directly in front of a moving vehicle and not to use a telephone or other electric devices. The considerations were also aimed at clarifying the obligations, related to pedestrians rights, of the driver of the vehicle approaching the pedestrian crossing, consisting in reducing the speed so as not to endanger the pedestrian on this crossing or entering it, and giving way to a pedestrian entering the zebra crossing. To achieve these goals, research methods such as the analysis of the normative text together with linguistic and logical methods were used. The article is important as it clarifies the controversy arising from Art. 13 (1a) of the Act on Road Traffic primarily to road traffic experts, drivers and pedestrians.

13

Możliwości odtworzenia prędkości pojazdu na podstawie nagrania z kamery pokładowej

Tokař Stanislav

Paragraf na Drodze

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2022

|

Nr 1

43--54

PL

Na podstawie dwóch zdarzeń drogowych pokazano, jakie są możliwości ustalania prędkości pojazdów przed kolizją z wykorzystaniem analizy nagrań wideo pochodzących z kamer pokładowych i geodezyjnego pomiaru miejsca zdarzenia. Pozyskane informacje pozwoliły na odtworzenie ruchu uczestników kolizji przy wykorzystaniu metody modelowania symulacyjnego, co dało możliwość wskazania na przyczyny kolizji.

EN

On the basis of two road traffic incidents the possibilities of specifying vehicles speeds prior to collision by analysing the video recordings from on-board cameras and geodetic measurements are shown. Owing to the thus obtained data it was possible to reconstruct the movements of the participants of the collisions, using the simulation modelling method, which enabled the identification of the causes of the collisions.

14

Simulation features of the impeller in a centrifugal pump

Mykhailiuk Vasyl, Fafaley Oleh, Deynega Ruslan, Mosora Yurii

Mining Machines

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2022

|

vol. 40, iss. 1

1--7

EN

To ensure the operability of machinery and equipment for the oil and gas industry, it is important to study their operation with subsequent improvement. This scientific work is devoted to highlighting the operation simulation of the impeller in a submersible centrifugal pump, because the pump itself is the main equipment in oil production. The main parts of a submersible centrifugal pump are its stages, consisting of an impeller and a guide vane. When the impeller rotates, a force interaction of the flow with the impeller blades occurs, while a pressure difference in the fluid flow on both sides of each blade arises. The pressure forces of the blades on the flow create a forced rotational and translational motion of the fluid, increasing its mechanical energy. It should be noted that the movement of fluid in pump sections is a rather complex process that is difficult to accurately describe analytically. However, today there are various computer programs (SOLIDWORKS FlowSimulation, ANSYS CFD, etc.) based on the finite volume method (FVM). To study the operation of a submersible centrifugal pump impeller, there has been built its threedimensional model. As a result of calculations, the distribution of pressure and velocity in the cross section of the impeller was obtained.

15

The influence of the police on vehicle speed in built-up areas

Dębiński Marcin, Bohatkiewicz Janusz

Budownictwo i Architektura

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2022

|

Vol. 21, no 2

17--30

EN

In many cases, the effects of road accidents have significant impact on human health. This translates directly into society, in both material and emotional terms. The severity of the injury in a road event depends largely on the speed of the vehicles. Excessive vehicle speed is of particular concern in incidents involving vulnerable road users. As confirmed by literature analysis and research, in most cases drivers do not respect the speed limits introduced by the road signs. Existing solutions allow to introduce permanent or temporary speed control. This paper investigates speeding and driver behaviour in built-up areas near schools and pedestrian crossings. The aim of the research described in the paper is to determine the influence of the effectiveness of police actions on speed reduction and improvement of road safety.

16

Effect of the wind speed and direction on energy balance in building

Pilarska Malwina

Polish Technical Review

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2021

|

No. 2

35--40

EN

In the present paper, the problems connected with the direction and velocities of the wind, having a significant effect on energy balance in a building, have been discussed. The discussed issue concerns the construction object (10-floor skyscraper) being shielded with many obstructions, which is affected by wind activity. The analysis concerns also the balance of heat energy of the discussed building which serves keeping of thermal comfort and by this, it is a summarization of heat profits in the building, obtained from internal heat sources and solar profits, connected with the losses, caused by heat transfer via external construction baffles and ventilation system. The problem connected with the wind and its role in the energy balance has been also presented. Apart from a good thermal insulation of external baffles, the coefficient of heat loss caused by heat transfer plays also a meaningful role. The mentioned building has been subjected to analysis which concerns the impact of the direction and speed of the wind on the heat transfer coefficient. The aim of the study was to determine the influence of the direction and speed of the wind on the value of heat transfer coefficient. As far as the dynamic values of surface heat coefficient are concerned, they have been presented in the table.

PL

W artykule zostały poruszone zagadnienia związane z kierunkiem oraz prędkością wiatru, który ma istotny wpływ na bilans energii w budynku. Została poruszona tutaj kwestia, która dotyczy obiektu budowlanego (10 piętrowego wieżowca) osłoniętego wieloma przeszkodami, na który ma wpływ działanie wiatru. Analiza dotyczy również bilansu energii cieplnej budynku , która służy do utrzymania komfortu cieplnego, a tym samym stanowi sumaryczne zestawienie zysków ciepła w budynku otrzymanego z wewnętrznych źródeł ciepła oraz zysków solarnych związanych ze stratami spowodowanymi przenikaniem przez zewnętrzne przegrody budowlane oraz wentylację. Została również przedstawiona kwestia związana z wiatrem oraz jego rolą w bilansie energii. Oprócz dobrej izolacji termicznej przegród zewnętrznych duże znaczenie ma tutaj współczynnik strat ciepła przez przenikanie. Budynek został poddany analizie, która dotyczy kierunku i prędkości wiatru na współczynnik przenikania ciepła, badanie miało na celu ustalenie jaki wpływ na wartość współczynnika przenikania ciepła ma kierunek i prędkość wiatru. Jeżeli chodzi o wartości dynamiczne przejmowania ciepła na zewnętrznej powierzchni zostały przedstawione w pracy w tabeli.

17

Prędkość ruchu dziecka na hulajnodze. Wyniki badań pilotażowych

Wyznakiewicz Paweł

Paragraf na Drodze

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2021

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Nr 2

67--73

PL

W artykule przedstawiono wyniki badań pilotażowych czasu przemieszczania się na zadanym odcinku drogi chłopca w wieku 11 lat na hulajnodze napędzanej siłą mięśni. Wykonując badania drogowe określano czas przejazdu hulajnogą odcinka pomiarowego długości 10 m ze stałą prędkością, a także czas przejazdu tego samego odcinka pomiarowego ze startu zatrzymanego. Próby wykonano dla jazdy wolnej, normalnej szybkiej. Podano wartości minimalne, maksymalne oraz wyznaczono średnie wartości czasów w zależności od tempa poruszania się. Na podstawie uzyskanych wyników obliczono średnie wartości prędkości hulajnogi, które wynoszą 2,6 m/s dla jazdy wolnej, 3,2 m/s dla jazdy normalnej i 4,5 m/s dla jazdy szybkiej.

EN

The aim of the article is to present the results of pilot studies on the time of covering a given distance by an 11-year-old boy on a human powered scooter. In the road tests the time of covering the distance of 10 m on a scooter at a constant speed and the time of covering this distance from a standing start were established. The tests were performed for a slow, normal and fast runs. The minimal and maximal values were given, and mean times vs. movement speed identified. Based on the results the mean values of the scooter movement were calculated: 2.6 m/s for slow run, 3.2 m/s for normal run and 4.5 m/s for fast run.

18

Jak biegły do spraw wypadków drogowych „może” wypowiadać się o intencjach obwinionego?

Księżopolski Jacek

Paragraf na Drodze

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2021

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Nr 3

55--66

PL

Artykuł przedstawia metodę opiniowania zdarzeń drogowych, udokumentowanych zapisem monitoringu, w których istnieje podejrzenie świadomego sprowokowania kolizji przez jednego z uczestników. Rozważania oparto na konkretnym zdarzeniu, w którym taką możliwość sugerowały zarówno dowody osobowe, jak i informacje o uczestniczeniu jednego z kierujących w dużej ilości podobnych zdarzeń drogowych. Pomimo że w przedmiotowej sprawie pytania skierowane do biegłego były sformułowane wyjątkowo ogólnikowo, to w istocie sprowadzały się do ustalenia, czy intencją obwinionego - kierującego, posiadającego pierwszeństwo przejazdu, było sprowokowanie zderzenia w okolicznościach wskazujących na odpowiedzialność drugiego uczestnika zdarzenia za jego wystąpienie. Oczywistym jest, że bezpośrednia odpowiedź na tego typu pytania byłaby skazana na zarzut przekroczenia kompetencji, ale odpowiednio przygotowana analiza może dać organowi procesowemu podstawę do samodzielnego ustalenia, jakie były intencje obwinionego.

EN

A method of producing expert opinions on road traffic accidents evidenced by monitoring system recording, in which one of the participants is suspected of having deliberately orchestrated the collision is presented. The discussion was based on an actual event in which such a possibility was suggested by both the witnesses’ testimony as well as information on the participation of one of the drivers in a large number of similar events. Despite the fact that the questions the court expert was asked were formulated in an extremely general way, they were essentially aimed at establishing whether it was the intention of the defendant - the driver who had the right of way to provoke the collision in circumstances indicating the responsibility of the other participant. Obviously, a direct answer to this type of question was doomed to the complaint of exceeding the competences. However, an adequately formulated analysis may provide the judicial authority with a basis for an independent decision as to what the defendant’s intentions were.

19

Modelling of work of the rotor-type blade pump with revolving stator

Dmytriv V. T., Lanets O. S., Dmytriv I. V., Horodetskyy I. M.

International Journal of Applied Mechanics and Engineering

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2021

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Vol. 26, no. 4

17--28

EN

In the article, the analytical dependences of modelling the cell cross-sectional area between two adjacent blades of a rotary blade pump and capacity for a pump with fixed and rotating stators are given, and analytical dependences are derived to model the power necessary to overcome the friction forces of the blades. The forces acting on the radially placed blade of a rotary pump with a fixed stator (non-rotating or stationary) and a rotating stator are analyzed. Design and technological parameters that influence the pump capacity and power are taken into account. The power required for the movement of the pump blade without taking into account the compression of the air has the opposite character of the change as to the pump capacity The capacity of a rotary pump with a rotating stator is three times higher than that of a stationary stator. The rotary pump with a rotating stator, with six radially spaced blades, consumes 0.854 [kW] less power to overcome the blade friction of 1313 kW The results of modelling of the pump work are given.

20

Sight distances at unsignalized intersections: a comparison of guidelines and requirements for human drivers and autonomous vehicles

Magyari Zsofia, Koren Csaba, Kieć Mariusz, Borsos Attila

Archives of Transport

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2021

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Vol. 59, iss. 3

7--19

EN

Many traffic accidents are caused by unforeseen and unexpected events in a site that was hidden from the driver's eyes. Road design parameters determining required visibility are based on relationships formulated decades ago. It is worth reviewing them from time to time in the light of technological developments. In this paper, sight distances for stopping and crossing situations are studied in relation to the assumed visual abilities of autonomous vehicles. Current sight distance requirements at unsignalized intersections are based among others on speeds on the major road and on accepted gaps by human drivers entering or crossing from the minor road. Since these requirements vary from country to country, regulations and sight terms of a few selected countries are compared in this study. From the comparison it is remarkable that although the two concepts, i.e. gap acceptance on the minor road and stopping on the major road have different back-grounds, but their outcome in terms of required sight distances are similar. Both distances are depending on speed on the major road: gap sight distances show a linear, while stopping sight distances a parabolic function. In general, European SSD values are quite similar to each other. However, the US and Australian guidelines based on gap acceptance criteria recommend higher sight distances. Human capabilities and limitations are considered in sight field requirements. Autonomous vehicles survey their environment with sensors which are different from the human vision in terms of identifying objects, estimating distances or speeds of other vehicles. This paper compares current sight field requirements based on conventional vehicles and those required for autonomous vehicles. Visibility requirements were defined by three vision indicators: distance, angle of view and resolution abilities of autonomous cars and human drivers. These indicators were calculated separately for autonomous vehicles and human drivers for various speeds on the main road and for intersections with 90° and 60° angles. It was shown that the required sight distances are 10 to 40 meters shorter for autonomous vehicles than for conventional ones.