No abstract

The paper presents the methods to improve safety and quality of life of people living in the neighborhood of roads and the situation of road users by means of traffic calming. The focus is kept on positive impact of traffic calming measures on acoustic climate in the surrounding of roads. The paper also contains the characteristics of selected impacts of road traffic on the environment together with a general outline of traffic calming as an instrument to mitigate the negative influence. Various possibilities to frame the acoustic climate and reduce transport-related inconvenience by means of different traffic calming methods are present as well. Then a case study (regional road No 824 in Puławy) is used to assess the effectiveness of specific solutions of comprehensive traffic calming with regard to speed reduction and abatement of noise emissions. Analyses are based on measurements’ results (traffic volumes, driving speeds and noise levels) and on acoustic calculations performed by the authors as part of their own study (internal research & development program of EKKOM). On the basis of measurements’ results and calculations the paper also addresses the problem of lack of correction factors related to traffic calming in the calculation model and the one of errors in noise modeling while preparing the case study.

The noise generated at the interface between the wheels of vehicles and the road surface is well recognized in the literature worldwide. Many publications describe the phenomenon of reducing this kind of impact by silent road surfaces. A specific type of this noise is the sound generated by vehicles passing over the expansion joints of bridge structures. Due to the impulsive nature of this sound, it is very onerous for people living in the close vicinity of bridge structures. The passage of vehicles over expansion joints causes the formation of vibrations that are transmitted to the structural elements of bridge structures, which may cause the formation of the material sounds (especially arduous in the case of bridges with steel elements). An attempt to reduce this impact was made by making a prototype acoustic cover of the expansion joint on the selected bridge. The paper presents the results of research on the “in situ” acoustic effectiveness of this cover. Additionally, the noise was modelled in the object surroundings before and after the cover’s application. The acoustic efficiency of the cover in the whole measured frequency range was 5.3 dBA. In the narrower frequency bands (1/3 octave bands), larger sound level reductions were observed. The maximum sound levels measured under the tested dilatation were less than 10.0 dBA lower than the maximum sound levels measured under the reference dilatation.

road noise constitutes one of the most adverse impacts of road traffic on the environment. noise that is particularly annoying for local inhabitants is recorded in the vicinity of engineering structures where various types of expansion joints are used [1][2][3]. There are currently many road connections being built in Poland, including a total of almost ten thousand expansion joints. The authors of this article attempt to determine the noise differences of several of the most commonly used expansion joints -single-, double-, and multimodule, block and finger expansion joint described as one of the most advantageous from the acoustic point of view. This study also attempts to determine the im-pact of expansion joint types on the noise level in comparison to the road section not equipped with these devices, which was adopted as the base noise level.

Current literature on the performance characteristics of road surfaces is primarily focused on evenness, roughness and technical durability. However, other important surface properties require analysis, including noisiness, which is an important feature of the environmental impact of vehicular traffic around roads. This can be studied using various methods by which road noise phenomena are investigated. The method used to measure the noise performance of road surfaces herein is the Statistical Pass-By (SPB) method, as described in ISO 11819-1:1997. The impedance tube method was used for sound absorption testing, as described in ISO 13472-2:2010. These tests were performed under a variety of conditions: in situ and in laboratory. The existence of relationships between them can be helpful in selecting surfaces for noise reduction. Preliminary surface noise tests can be performed in the laboratory with samples consisting of various compounds. This is less expensive and faster than doing so on purpose-built surfaces. The paper presents study results for sound absorption coefficients of various types of low-noise surfaces in in situ conditions (on an experimental section and on operated road sections) and in the laboratory setting. The results of the tests performed on the operational sections were compared to the results of the surface impact on road noise using the SPB method. The correlations between the test results help confirm the feasibility of road surface pre-testing in the laboratory and the relation to tests performed using the SPB method under typical operating conditions.