Categorisation of probability distributions of traffic noise indicators by road type

MINIATURA 5

Funding Organization: National Science Centre

Project title: Categorisation of probability distributions of traffic noise indicators by road type

Agreement number: DEC-2021/05/X/ST8/00775

Project implementation period: 02.12.2021 - 01.06.2023

Principal Investigator: dr Bartosz Zbigniew Przysucha

Project value: 32 475,00 PLN

Funds granted for Lublin University of Technology: 32 475,00 PLN

Abstract: The analysis of noise indicators used to control the acoustic condition of the environment is an important issue of mechanical engineering in general. Noise indices are a fundamental tool used in environmental noise management. They are commonly used in acoustics to calculate equivalent sound levels at appropriate times. The daytime, evening, nighttime, and day/evening/nighttime indices are the sound levels averaged according to Weber-Fechner's law over a year. It is technically not possible to monitor sound levels as required by the act throughout the year. An assessment of indicators from random measurements is therefore made. The indicators are therefore calculated on the basis of a measurement sample of several elements. Together with such an assessment it is also necessary to provide the uncertainty of noise indicators. The basic problem in determining the uncertainty is the form of the probability distribution of the noise indicators. The basic assumption in determining the uncertainty of noise indicators is the assumption of normality of noise indicators or sound energy levels, or rapid convergence of the mean of these variables to a normal distribution. However, literature studies show that this assumption is very often not fulfilled. Furthermore, uncertainty determinations by standard methods under the above assumptions very often lead to uncertainty intervals that do not meet the basic criterion for an uncertainty interval (95% confidence interval).
This generates a problem related to management of funds for environmental protection against road and air traffic noise. Validation of acoustic maps or reliability of acoustic measurements.
Knowing the form of probability distribution of noise indicators, one can properly choose the methodology of uncertainty determination and thus ensure the reliability of estimated parameters (noise indicators) required by standards and regulations. The research activity will be to categorize the probability distributions of noise indicators used in environmental protection against road noise with respect to road type. The research problem will be implemented with the University of Salerno, Department of Industrial Engineering in the framework of a research internship. This center has been selected as one of the best centers in the world for road noise research. Contact with the center has been made with Professor Alessandro Ruggiero to establish scientific cooperation in the above mentioned research topic. The first stage of the research will be to categorize roads in terms of size: local roads, expressways, national roads, urban roads with different vehicle volumes. The second way of categorization will be road construction. One-, two-, three-, four-lane roads. One-way and two-way, divided or not by a green belt. The third criterion would be the percentage composition of vehicles using the roads (light and heavy). These roads would be selected in an analogous way for both Poland and Italy, so that measurement results could be compared both within and between countries. The selection of the measurement sample would be representative and the measurements would be performed in accordance with the measurement standards described in the international standard ISO 1996-2:2017. During the performance of the measurements, traffic volume and weather conditions would also be measured.