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Low Noise Road Surfacing (LNRS) Materials

To improve the quality of life, we have been striving to develop new low noise road surfacing (LNRS) materials for use in Hong Kong. In 2016, we engaged the Hong Kong Polytechnic University (PolyU) to study the use of a new LNRS material suitable for local roads in Hong Kong called "6mm Polymer Modified Stone Mastic Asphalt"(PMSMA6), which 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 conducted the site trial program of PMSMA6 for about 50 local roads from 2019 to 2023. Based on the outcomes of the site trial program, we issued guidance notes RD/GN/038B and RD/GN/011D in February 2023, which updated the technical guidelines for the application of PMSMA6 as an LNRS material on local roads in Hong Kong.

Following the release of our updated guidance notes on LNRS, we have initiated another site trial program for "6mm Highly Modified Stone Mastic Asphalt" (HMSMA6) in late 2023. This site trial program will encompass 20 trial road sections. Based on encouraging laboratory results, HMSMA6 demonstrates superior performance in rutting resistance compared to PMSMA6. We will complete these site trials as soon as possible, with the aim of establishing a set of application criteria for this more durable LNRS material.