scholarly journals THE EXPERIMENTAL STUDY OF SHALLOW FLOWS OF LIQUID ON THE AIRPORT RUNWAYS AND AUTOMOBILE ROADS

Transport ◽  
2010 ◽  
Vol 25 (4) ◽  
pp. 394-402 ◽  
Author(s):  
Andrey Beljatynskij ◽  
Olegas Prentkovskis ◽  
Julij Krivenko

Hydroplaning or aquaplaning is associated with the complete loss of the grip of a tyre because of the presence of a water film between the tyres of a moving vehicle (an automobile, an airplane, etc.) and the road surface. In this case, a vehicle becomes uncontrollable. Hydroplaning (aquaplaning) occurs when the speed of a vehicle reaches the critical value, when the wheel does not have time enough for water compulsion, which leads to the formation of a permanent water film between it and the road surface. The higher the depth of the water on the road surface under the tyre, the higher the risk of hydroplaning (aquaplaning). In other words, hydroplaning (aquaplaning) is the floating of the wheel on the water wedge. In physical terms, it is the loss of the ability of a tyre of the effective water compulsion from the contact area with the road. As a result, a water film of several millimeters is formed under the wheel, and a vehicle actually floats up. The article presents the results obtained in the experimental study of the flows of liquid, whose depth is comparable with that of depressions and cambers of rough roadway pavement. It is stated that the relationships used for calculating surface flows should be corrected for shallow flows, taking into account the actual roughness of road covering. Shallow flows are mostly laminar. The transition Reynolds numbers are about 3000. The relationships used for calculating shallow flows may be determined more accurately by test pouring of water on the surface of roadway pavement, with further generalization of the data. The experimental research performed is closely related to the study of the problems of aquaplaning and traffic safety of various means of transport.

2018 ◽  
Vol 1 (3) ◽  
pp. 667-678
Author(s):  
Mulyadi Mulyadi ◽  
Muhammad Isya ◽  
Sofyan M. Saleh

Abstract: Blangkejeren - Lawe Aunan road conditions overall is on the slopes of the mountains which is strongly influenced by local environmental factors such as drainage, topography, soil conditions, material conditions and vehicle load conditions across the road. It should be noted in order to avoid a decrease in the road quality due to road surface damage that can affect the traffic safety, comfort and smoothness.. Therefore, it is necessary to study the evaluation of the condition of the damaged road surface and the local factors that affect the damage in order to avoid a decrease in the roads quality. This study took place on Blangkejeren - Lawe Aunan roads started from Sta. 529 + 700 - Sta. 535 + 206. Generally, the condition of roads in this segment were found damage that disturb the comfort, smoothness and safety of the roads users. In this study, the primary data obtained by actual surveys in the form of data field length, width, area, and depth of each type of damage as well as local factors that lead to such damage. Actual field surveys conducted along the 5.506 km, with the distance interval of each segment is 100 m. The secondary data obtained from the relevant institutions and other materials related to this research. This study analyzed the PCI method (Pavement Condition Index) to obtain the level of damage in order to know how to handle, while for the identification of the damage done by observation factors descriptively appropriate observation in the field such as the number of damage points. The results of this study found that the type of damage caused to roads is damage to the cover layer, a hole, and curly. This type of damage that commonly occurs on the road Blangkejeren - Lawe Aunan is damage to the edges with a percentage of 87.30%. The local factors that greatly affect drainage on the percentage of damage is 62.00%. PCI average value is 13.47 which indicates a very bad condition (very poor) and requires maintenance or improvement of reconstruction.Abstrak: Kondisi jalan Blangkejeren – Lawe Aunan secara keseluruhan berada di lereng pegunungan sangat dipengaruhi oleh faktor lingkungan setempat seperti drainase, topografi, kondisi tanah, kondisi material dan kondisi beban kendaraan yang melintasi jalan tersebut. Hal ini perlu diperhatikan agar tidak terjadi penurunan kualitas jalan akibat kerusakan permukaan jalan sehingga dapat mempengaruhi keamanan, kenyamanan, dan kelancaran dalam berlalu lintas. Oleh karena itu, perlu dilakukan penelitian evaluasi terhadap kondisi permukaan jalan yang mengalami kerusakan serta faktor setempat yang mempengaruhi kerusakan tersebut agar tidak terjadi penurunan kualitas jalan. Penelitian ini mengambil lokasi di ruas jalan Blangkejeren – Lawe Aunan yang dimulai dari Sta. 529+700 - Sta. 535+206. Umumnya kondisi ruas jalan pada segmen ini banyak ditemukan kerusakan-kerusakan yang dapat mengganggu kenyamanan, kelancaran, dan keamanan pengguna jalan. Dalam penelitian ini data primer diperoleh dengan melakukan survei aktual lapangan yaitu berupa data panjang, lebar, luasan, dan kedalaman tiap jenis kerusakan serta faktor setempat yang mengakibatkan kerusakan tersebut. Survei aktual lapangan dilakukan sepanjang 5,506 km, dengan jarak interval setiap segmen adalah 100 m. Adapun data sekunder diperoleh dari lembaga terkait dan bahan lainnya yang berhubungan dengan penelitian ini. Penelitian ini dianalisis dengan metode PCI (Pavement Condition Index) untuk mendapatkan tingkat kerusakan agar diketahui cara penanganannya, sedangkan untuk identifikasi faktor kerusakannya dilakukan dengan pengamatan secara diskriptif sesuai hasil pengamatan di lapangan berupa jumlah titik kerusakan. Hasil penelitian ini didapatkan bahwa jenis kerusakan yang terjadi pada ruas jalan adalah kerusakan lapisan penutup, lubang, dan keriting. Jenis kerusakan yang umum terjadi pada ruas jalan Blangkejeren – Lawe Aunan adalah kerusakan tepi dengan persentase 87,30 %. Faktor setempat yang sangat mempengaruhi kerusakan adalah drainase dengan persentase 62,00%. Nilai PCI rata-rata yaitu 13,47 yang menunjukkan kondisi sangat buruk (very poor) dan memerlukan pemeliharaan peningkatan atau rekonstruksi.


2021 ◽  
Vol 20 (3) ◽  
pp. 216-223
Author(s):  
Yu. V. Burtyl ◽  
M. G. Salodkaya ◽  
Ya. N. Kovalev

The design of road surfaces involves application of  a sophisticated algorithm system based on mathematical calculations and engineering solutions, with the calculation of evaluation criteria.  It is precisely the observance of the standardized requirements in terms of design criteria that makes it possible to consider the design of the pavement as reliable, and the road as safe and convenient for traffic during the specified service life. When calculating the strength, based on the predicted traffic intensity and the composition of the traffic flow, calculations are carried out according to the main criteria: admissible elastic deflection, shear in layers of non-reinforced materials and in asphalt concrete, as well as the ultimate tensile stresses in cast-in-situ materials with the specified reliability level.  However, in the accepted concepts for  calculating the strength and reliability of road pavements,  only the force effect is directly taken into account. To take into account environmental factors, it is necessary to develop a comprehensive indicator of the resulting impact of all factors. The paper presents a complex of factors influencing on traffic safety, road deformations and irregularities the height of unevenness, in particular, an increase in the dynamic impact on the road and the amplitude of vibration of a car wheel on a road with an uneven surface (when detached from the road surface), the coincidence of the vibration frequency of the car with the natural frequencies of vibration of the road surface, and as a consequence, on the behavioral features of driving. The arguments have been substantiated that the predictive models do not take into account a number of factors that have a significant impact on the formation of irreversible deformation in the layers of materials of road structures.


1967 ◽  
Vol 40 (3) ◽  
pp. 684-693 ◽  
Author(s):  
Barbara E. Sabey

Abstract When roads are wet their skidding resistance is reduced by the lubricating action of the film of water on the road. Under some circumstances this reduction may be substantial and the extent of it is largely dependent on the characteristics of the road surface. The first requirement for a good skidding resistance on wet roads is to facilitate break through of the water film in order to establish areas of dry contact between the road and the tire. Drainage channels, provided by the large scale texture of the road or by a pattern on the tire, assist in getting rid of the main bulk of water and are of increasing importance the higher the speed. The penetration of the remaining water film can be achieved only if there are sufficient fine scale sharp edges in the road on which high pressures (about 1000 lb/in2) are built up. The existence of such fine scale sharpness gives the surfaces a harsh feel. When vehicles are travelling at speeds of about 30 mph the fine scale texture of the road is the dominant factor determining skidding resistance. However, as they travel faster, it becomes increasingly difficult to penetrate the water film in the time available, however harsh the surface. At high speeds the requirements for a good skidding resistance are therefore different. The resistance to skidding arises to a larger extent from energy losses in the rubber of the tire as the surface of the tread is deformed by projections in the road surface and, although the physical properties of the tread rubber are important in this respect, it is essential to have sufficiently large and angular projections in the road surface to deform the tread, even though a water film may still be present on the surface. At higher speeds the coarseness of texture becomes as important as its harshness.


2021 ◽  
pp. 100077
Author(s):  
Samim Mustafa ◽  
Hidehiko Sekiya ◽  
Aya Hamajima ◽  
Iwao Maeda ◽  
Shuichi Hirano

Author(s):  
Tomislav Petrović ◽  
Miloš Milosavljević ◽  
Milan Božović ◽  
Danislav Drašković ◽  
Milija Radović

The application of intelligent transport systems (hereinafter ITSs) on roads enables continuous monitoring of road users during a whole year with the aim to collect good-quality data based on which the more complex analyses could be done, such as monitoring of certain traffic safety indicators. Automatic traffic counters are one of the most commonly implemented ITSs for collecting traffic flow parameters that are relevant for traffic management on state roads in Republic of Serbia. This paper presents one of the possible ways to collect, analyze and present data on road users’ speeds using automatic traffic counters, where certain traffic safety indicators are analyzed in terms of road users’ compliance with the speed limit on the road section from Mali Pozarevac to Kragujevac. Based on the analyses of data downloaded from automatic traffic counters, it is observed that an extremely high percentage of vehicles drive at speed higher than the speed limit, indicating clearly to higher traffic accident risk, as well as to the need for a tendency to implement speed management on roads using ITS in the forthcoming period.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Choong Heon Yang ◽  
Jin Guk Kim ◽  
Sung Pil Shin

Road surface conditions have a direct effect on the quality of driving, which in turn affects overall traffic flow. Many studies have been conducted to accurately identify road surface conditions using diverse technologies. However, these previously proposed methods may still be insufficient to estimate actual risks along the roads because the exact road risk levels cannot be determined from only road surface damage data. The actual risk level of the road must be derived by considering both the road surface damage data as well as other factors such as speed. In this study, the road hazard index is proposed using smartphone-obtained pothole and traffic data to represent the level of risk due to road surface conditions. The relevant algorithm and its operating system are developed to produce the estimated index values that are classified into four levels of road risk. This road hazard index can assist road agencies in establishing road maintenance plans and budgets and will allow drivers to minimize the risk of accidents by adjusting their driving speeds in advance of dangerous road conditions. To demonstrate the proposed risk hazard assessment methodology, road hazards were assessed along specific test road sections based on observed pothole and historical travel speed data. It was found that the proposed methodology provides a rational method for improving traffic safety.


2021 ◽  
Vol 67 (4) ◽  
pp. 1-8
Author(s):  
Jacob Adedayo Adedeji ◽  
Xoliswa Feikie

Road traffic fatality is rated as one of the ten causes of death in the world and with various preventive measures on a global level, this prediction is only placed on flat terrain and didn’t reduce. Nevertheless, road users’ communication is an essential key to traffic safety. This communication, be it formal or informal between the road users is an important factor for smooth traffic flow and safety. Communication language on roads can be categorized into; formal device-based signal (formal signal), formal hand signal (formal signal), informal device-based signal (informal signal), and informal gesture-based signal (everyday signal). However, if the intent of the message conveys is not properly understood by the other road user, mistakes and errors may set in. Overall, the formal signal is based on explicit learning which occurs during the driving training and the license testing process and the informal, implicit learning occur during the actual driving process on the road unintentionally. Furthermore, since the informal signal is not a prerequisite to driving or taught in driving schools, novice drivers are clueless and thus, might have contributed to errors and mistakes which leads to traffic fatalities. Therefore, this study seeks to document the informal means of communication between drivers on South African roads. Consequently, a qualitative semi-structured interview questionnaire would be used in the collection of informal signals, which were predominantly used on South African roads from driving instructors and thereafter, a focus group of passengers’ car, commercial and truck drivers will be used to validate the availability and their understanding of these informal signals using a Likert-type scale for the confidence level. In conclusion, the information gathered from this study will help improve road safety and understanding of road users especially drivers on the necessity of communication and possible adaptation for other developing countries.


2021 ◽  
pp. 38-40
Author(s):  
А.Р. Исмагилова

В статье раскрываются полномочия сотрудников подразделений пропаганды Государственной инспекции безопасности дорожного движения в целях профилактики дорожно-транспортных происшествий и травматизма на дороге. The article reveals the powers of the employees of the propaganda units of the State Traffic Safety Inspectorate in order to prevent road accidents and injuries on the road.


Author(s):  
Abdulmajeed Alamri ◽  
Tarek M. Esmael ◽  
Sami Fawzy ◽  
Hany Hosny ◽  
Saleh Attawi ◽  
...  

In this study, road traffic injury (RTI) was defined as any injury resulting from a road traffic accident irrespective of severity and outcome. Road traffic accident (RTA) was defined as any crash on the road involving at least one moving vehicle, irrespective of it resulting in an injury. This could include collision with a vehicle or any non`moving object while driving/riding a vehicle, collision with a moving vehicle while walking/running/standing/ sitting on the road, or fall from a moving vehicle. The burden of road traffic accidents (RTA) is a leading cause of all trauma admissions in hospitals worldwide. Road traffic injuries cause considerable economic losses to victims, their families, and to nations as a whole. These losses arise from the cost of treatment (including rehabilitation and incident investigation) as well as reduced/lost productivity (e.g. in wages) for those killed or disabled by their injuries and for family members who need to take time off work (or school) to care for the injured. Road traffic fatality in the Kingdom of Saudi Arabia (KSA) is the highest, accounts for 4.7% of all mortalities. Road injuries also are reported to be the most serious in this country, with an accident to injury ratio of 8:6. In this study, we try to focus on some causes of the accidents in KSA, so we can implement the prevention plan.


Author(s):  
Zhenyao Zhang ◽  
Jianying Zheng ◽  
Hao Xu ◽  
Xiang Wang

The problem of traffic safety has become increasingly prominent owing to the increase in the number of cars. Traffic accidents often occur in an instant, which makes it necessary to obtain traffic data with high resolution. High-resolution micro traffic data (HRMTD) indicates that the spatial resolution reaches the centimeter level and that the temporal resolution reaches the millisecond level. The position, direction, speed, and acceleration of objects on the road can be extracted with HRMTD. In this paper, a LiDAR sensor was installed at the roadside for data collection. An adjacent-frame fusion method for vehicle detection and tracking in complex traffic circumstances is presented. Compared with the previous research, objects can be detected and tracked without object model extraction or a bounding box description. In addition, problems caused by occlusion can be improved using adjacent frames fusion in the vehicle detection and tracking algorithms in this paper. The data processing procedure are as follows: selection of area of interest, ground point removal, vehicle clustering, and vehicle tracking. The algorithm has been tested at different sites (in Reno and Suzhou), and the results demonstrate that the algorithm can perform well in both simple and complex application scenarios.


Sign in / Sign up

Export Citation Format

Share Document