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Low Noise Road Surfacing (LNRS) Materials

To improve the quality of life, we have been striving to develop low noise road surfacing (LNRS) materials. Although the existing LNRS can reduce road tyre noise, it is not suitable for road sections with steep vertical gradient and road sections with frequent sharp turning/braking expected. To overcome these limitations, we engaged the Hong Kong Polytechnic University in 2016 to study the use of a new LNRS material suitable for local roads called “6mm Polymer Modified Stone Mastic Asphalt” (PMSMA6). PMSMA6 is made of fine-grained gap-graded bituminous mixtures. Its smooth and optimized surface texture not only provides a noise reducing property to alleviate traffic noise impact but also improves riding comfort for road users.

With positive laboratory test results, we commenced the site trial programme of PMSMA6 in local roads in 2019. So far, trials on this new material in 36 road sections have been conducted as at end-Sep 2021. The selected road sections covered various road characteristics such as stop lines, bus stops, inclined roads and sharp turning. Based on the results of these trial road sections, an interim report has been completed in June 2021 summarizing the suitability of applying PMSMA6 at road sections with different road characteristics. We endeavor to lay more road sections with PMSMA6 with a view to establishing a set of criteria for general application of this new LNRS material.