Scientific Journal of Silesian University of Technology. Series Transport

10

Authors: Piotr GORZELANCZYK

Every year, a large number of traffic accidents occur on Polish roads. However, the pandemic of recent years has reduced the number of these accidents, although the number is still very high. For this reason, all measures should be taken to reduce this number. This article aims to forecast the number of road accidents in Poland. Thus, using Statistica software, the annual data on the number of road accidents in Poland were analyzed. Based on actual past data, a forecast was made for the future, for the period 2022-2040. Forecasting the number of accidents in Poland was conducted using selected neural network models. The results show that a reduction in the number of traffic accidents is likely. The choice of the number of random samples (learning, testing and validation) affects the results obtained.

11

Authors: Onyedikachi Chioma OKORO, Maksym ZALISKYI, Dmytriiev SERHII, Ibinabo ABULE

Data-driven predictive aircraft maintenance approach typically results in lower maintenance costs, avoiding unnecessary preventive maintenance actions and reducing unexpected failures. Information provided by a reliability analysis of aircraft components and systems can improve an existing maintenance strategy and ensure an optimal maintenance task interval. For reliability work, the exponential distribution is typically used; however, this approach requires substantial amounts of data, which often may not be generated by aviation operations. Therefore, this study proposes a method for reliability analysis given a small dataset. Real-life historical data of an aircraft operating in Nigeria validate the proposed approach and prove its applicability.

12

Authors: Oleksiy BAZHINOV, Mikhail KRAVTSOV, Tetiana BAZHYNOVA, Yevhen HAIEK, Serhii KHARCHENKO, Taras SHCHUR, Katarzyna MARKOWSKA, Agnieszka SĘKALA, Kinga STECUŁA, Tomasz KAWKA, Ewa SIUDYKA

This article presents theoretical studies of methods for assessing car quality indicators in the operation stage. Important criteria for determining the quality indicators of cars during the operation phase are the following: functional stability, ecology, comfort, technical solutions, and traffic safety. The problem of converting a multicriteria quality assessment to a single criterion is proposed to be solved by the method of determining a quality index. The methodology for the practical and actual implementation of this research is based on the evaluation of the quality index established on the average vehicle speed then the basic methodological principles are formulated. The quality index of a car is significantly dependent on the operating conditions. This article presents the correction coefficients for the quality index of base, hybrid, and electric vehicles, depending on the operating conditions. The studies and the proposed car quality index provide timely information on the characteristics of operating conditions, creating the necessary conditions and opportunities for automakers to improve the design of cars, promote the image of car brands, and increase sales.

12

Authors: Oleksiy MELNYK, Svitlana ONYSHCHENKO, Oleg ONISHCHENKO

Reduction of ecological risks of shipping is a challenging task that requires methods of legislative and regulatory control, organizational measures, and technical and technological support. Furthermore, the matter concerns not only the reduction of possible risks but also the level of existing impact on the marine environment because of exhaust gas emissions by ships, discharge of waste and ballast water, as well as control of ecological consequences of accidents. The purpose of this study is to analyse possible sources of environmental impact during ship operation cycles, identify significant risks, review existing potentials to reduce the risk of ship accidents and their environmental consequences, and develop solutions to existing problems. This study offers results, which can serve as the initial basis for the formation of comprehensive measures on the reduction of environmental risks, and consequences of possible accidents for the environment caused by ships and international shipping.

13

Authors: Lesław ZABUSKI

This paper presents the results of a stability analysis of a slope located in the immediate vicinity of a railway line. The plans for the extension of this railway track include the construction of another line, which would run parallel to the existing one, within a few metres distance. It is expected that intensive goods train traffic will generate both static and dynamic forces in the underlying subsoil. Consequently, seismic vibrations will be generated in the subsoil, propagating mainly not only in the horizontal direction but also in the vertical direction. The method of seismic coefficient of the earthquake intensity determined by a pseudo-static method and horizontal component of acceleration is appropriate and recommended because it is simple, and the safety factor of the slope is calculated in the same way as in conventional stability calculations.

15

Authors: Mulugeta GIRMA

In emerging countries, improving performance in the transportation industry is a critical concern. Bus transport companies like Anbessa, Sheger and the Public Service Employees' Transport Service play a pivotal role in Addis Ababa's transit system. Subsequently, this study analyzes the operators' operational performance, comparing it to industry norms. The collected data is analyzed using the ratio analysis approach. The findings indicate that the Anbessa City Bus outperforms the other buses in several aspects, such as fleet strength, service utilization, and vehicle utilization, but there is a disparity in staff productivity and operational safety. Sheger City Bus, on the other hand, outperforms the market in terms of vehicle utilization, workforce productivity, and operational safety. However, on most of the indicators, the Public Employees Bus performs the worst. Finally, comparing the operators' performance to industry standards, most indications show that they fail to meet. Consequently, even if bus transit operators are subsidized by the government in the operation of their services for residents, the study suggests that they must make significant improvements in how they use their resources to improve their financial and operational performance and deliver better services compared to those provided by other operators in the city. In addition, government incentives such as subsidies should be allocated based on actual operational performance.

15

Authors: Kamil KRASUSKI, Małgorzata KIRSCHENSTEIN

This paper presents the results of a study on the use of different tropospheric correction models in SBAS positioning for air navigation. The paper, in particular, determines the influence of the Saastamoinen troposphere and RTCA-MOPS models on the determination of aircraft coordinates and mean coordinate errors in the SBAS positioning method. The study uses real kinematic data from a GPS navigation system recorded by an onboard GNSS satellite receiver as well as SBAS corrections. In the experiment, the authors include SBAS corrections from EGNOS and SDCM augmentation systems. The navigation calculations were performed using RTKLIB v.2.4.3 and Scilab 6.1.1 software. Based on the conducted research, it was found that the difference in aircraft coordinates using different troposphere models can reach up to ±2.14 m. Furthermore, the use of the RTCA-MOPS troposphere model improved the values of mean coordinate errors from 5 to 9% for the GPS+EGNOS solution and from 7 to 12% for the GPS+SDCM solution, respectively. The obtained computational findings confirm the validity of using the RTCA-MOPS troposphere model for SBAS positioning in aerial navigation.

21

Authors: Yuvraj GOYAL, Sanu MEENA, Suresh Kumar SINGH, Mukul KULSHRESTHA

Air quality problems in cities are often a cause for worry. The air quality index is increasing daily, leading to an increase in cancer and many respiratory problems. Road transport in an urban area is a significant cause of air pollution. The vehicles must meet Indian emission regulations for which the emissions are measured using legally mandated standard driving cycles that did not accurately reflect real-world driving emissions because of varying traffic conditions, meteorological conditions, driving behaviour, vehicle power, performance, etc. This study focuses on real-time emissions of gaseous pollutants hydrocarbon (HC), carbon dioxide (CO2), carbon monoxide (CO), and nitric oxide (NO) from vehicle exhaust pipes under heterogeneous traffic conditions. The emissions were measured using a Portable Emission Measurement System (PEMS). The PEMS used was an AVL MDS 450 analyser mounted on the vehicle, and on-road emissions were captured. The test sample consists of four passenger vehicles with varying engine sizes, manufacturers, and fuel. The test route comprises city and highway areas, and it was discovered that the emissions were reduced by 40 to 70% on highways compared to the city. In petrol BSIV and BSVI engines, the emission was reduced to 41.73% for CO, 46.90% for HC, and 64% for NO in the city area. Speed and emissions scatter graphs were plotted for the vehicles, and it was found that in the city area, the optimum speed for less emission is between 30-40 km/h, and on highways, the optimum speed is 80-90 km/h. The emissions were also sensitive to the rate and frequency of acceleration and decelerations. This type of study is very limited in India, and more such studies are required for the assessment of air quality in metropolitan areas and successful traffic management strategies, as well as for determining instantaneous projections of pollutant emissions.

22

Authors: Divya KWATRA, Kalaga Ramachandra RAO, Vasudha BHATNAGAR

Scientific analysis of public transport systems at the urban, regional, and national levels is vital in this contemporary, highly connected world. Quantifying the accessibility of nodes (locations) in a transport network is considered a holistic measure of transportation and land use and an important research area. In recent years, complex networks have been employed for modeling and analyzing the topology of transport systems and services networks. However, the design of network hierarchy-based accessibility measures has not been fully explored in transport research. Thus, we propose a set of three novel accessibility metrics based on the k-core decomposition of the transport network. Core-based accessibility metrics leverage the network topology by eliciting the hierarchy while accommodating variations like travel cost, travel time, distance, and frequency of service as edge weights. The proposed metrics quantify the accessibility of nodes at different geographical scales, ranging from local to global. We use these metrics to compute the accessibility of geographical locations connected by air transport services in India. Finally, we show that the measures are responsive to changes in the topology of the transport network by analyzing the changes in accessibility for the domestic air services network for both pre-covid and post-covid times.