Sound absorption of porous structures: a design tool for road surfaces

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.

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An Approach To Comparative Simulation Of Road Lighting and Estimation Of Associated Quality Parameters

Light & Engineering ◽

10.33383/2020-058 ◽

2021 ◽

pp. 77-87

Author(s):

Sourin Bhattacharya ◽

Suddhasatwa Chakraborty ◽

Susanta Ray

Keyword(s):

Lighting Design ◽

Quality Parameters ◽

Design Tool ◽

Programming Approach ◽

Design Standards ◽

Flexible Tool ◽

Road Lighting ◽

Road Surfaces ◽

Lighting Simulation ◽

Matlab Programming

A software-based comparative simulation work was conducted about the luminance-based method of road lighting design with MATLAB and DIALux, giving due consideration to the design standards laid down in CIE140:2019 technical report. The outputs were obtained for a specified set of road lighting conditions in terms of luminaire mounting height, road width, spacing of lighting poles, overhang, and maintenance factor for four different CIE standard road surfaces R1, R2, R3, and R4, six different observer positions and three types of luminai rearrangements. MATLAB and DIALux outputs were quantified by three quality parameters, namely: average luminance, overall uniformity and longitudinal uniformity of luminance, and the linear correlation between the two was found to be statistically significant (p < 0.00001). DIALux, as a graphical lighting design tool, was found to be more convenient than the algorithm-reliant MATLAB programming approach for general road lighting simulation. However, MATLAB programming approachcould facilitate experimental road lighting simulation, and the developed MATLAB program could be used as a flexible tool to simulate road lighting with experimental luminaire distribution curve of luminous intensity (I) and road surface reduced luminance coefficient (r) tables. Further developments upon it could potentially integrate provisions for luminaires with custom tilt and curved road surfaces.

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