Following is a question by the Hon Aaron Bok and a written reply by the Acting Secretary for Environment and Ecology, Miss Diane Wong, in the Legislative Council today (May 20):

Question:

     It is learnt that if road traffic noise cannot be reduced directly at source, the Government often needs to build a large number of facilities such as noise barriers and noise enclosures in road construction works, leading to substantial increases in road construction costs. In this connection, will the Government inform this Council:

(1) of the respective total expenditures incurred by the Government on noise mitigation measures in works for new road construction or road extension in the past two financial years and the current financial year to date, with a breakdown by items of (i) noise barrier, (ii) noise enclosure/semi-enclosure, (iii) low-noise road surface, and (iv) other indirect mitigation measures such as acoustic window/air-conditioning (including the item amounts and their proportions in the total costs of road works);

(2) of the respective numbers of road projects and lengths of relevant road sections for which the Government adopted (i) direct noise mitigation measures (including the use of low-noise road surfaces and speed management) and (ii) other mitigation measures (including noise barriers/noise enclosures) in the past two financial years and the current financial year to date;

(3) whether the authorities have put in place policies, technical guidelines or mandatory assessment frameworks for "prioritising noise source reduction" (for example, requiring a comparison of the benefits and feasibility of noise source reduction solutions versus noise barrier/noise enclosure solutions during the feasibility study and design stages of works); if so, of the details (including the assessment criteria and the vetting and approval procedures); if not, the reasons for that;

(4) whether the authorities will review the current road traffic noise mitigation strategy by designating "direct reduction of noise at source" as the priority option, as well as setting quantified targets and timetables in respect of works for new road construction and road improvement; if so, of the details and the estimated savings in works expenditure; if not, the reasons for that; and

(5) of the respective expenditures incurred in the past two financial years and the current financial year to date on the repair, maintenance and replacement of the noise barriers, noise enclosures and related facilities built; whether the authorities will conduct a review to compare the effectiveness of these measures and noise source reduction solutions; if so, of the details?

Reply:

President,

     The Government's overall policy objective for road traffic noise control is to attain and maintain a satisfactory traffic noise environment, thereby ensuring a better quality of life for the public and protecting them from excessive road traffic noise. The top priority is to avoid creating new environmental problems and seize opportunities available to reduce environmental noise. To this end, the Government has been striving to mitigate road traffic noise impacts on the public through a multi-pronged approach, including requiring project proponents to conduct traffic noise impact assessments when planning new developments, such as roads, residential developments and new towns/new development areas, so as to avoid creating new noise problems; and studying the use of low noise road surfacing materials for resurfacing existing road sections where traffic noise exceeds the standards, to reduce noise at source, or retrofitting noise barriers/enclosures along roads to block noise propagation, where practicable.

     Since 2000, the Environmental Protection Department (EPD) has been assessing the local population exposed to excessive traffic noise by producing the spatial distribution of traffic noise problem in Hong Kong, with regular updates of the relevant statistics. According to estimation, about 1.14 million people suffered from excessive traffic noise in 2000. Comparing 2020 to 2000, the local population has grown by about 820 000 (about 13 per cent), the road length by about 200 kilometres (about 13 per cent) and the number of registered vehicles by about 290 000 (about 57 per cent). Nonetheless, on account of the above multi-pronged initiatives, the local population exposed to excessive traffic noise has conversely dropped by about 460 000 (i.e., already decreased by 40 per cent) over the past 20 years.

     In response to the question raised by the Hon Aaron Bok, the reply as follows.

(1) The Government's annual expenditure on noise mitigation measures for road works projects varies depending on the number of projects involving road works, as well as the uniqueness of the respective projects and actual needs. According to information provided by the Civil Engineering and Development Department (CEDD) and the Highways Department (HyD), among the designated projects under the Environmental Impact Assessment Ordinance (EIAO) (Cap. 499) (designated projects) involving the construction of new major roads that obtained funding approval from the Finance Committee (FC) of the Legislative Council (LegCo) in the past two financial years, the estimated expenditure on various types of noise mitigation measures, as well as their respective proportion of the total project costs, are as follows:
 

Noise Mitigation Measures	Year 2024/25 Expenditure ($ million)   (6 works projects in total)	Year 2025/26 Expenditure ($ million)   (1 works project in total)
(i) Noise barriers	4,090 accounting for 4.3% of total project costs	1,520 accounting for 11.0% of total project costs
(ii) Noise enclosures/semi-enclosures	1,784 accounting for 1.9% of total project costs	0
(iii) Low noise road surfacing	248 accounting for 0.3% of total project costs	132 accounting for 1.0% of total project costs
(iv) Other indirect noise mitigation measures such as window insulation/air-conditioning	0	0

Note: For road works, low noise road surfacing is a measure that mitigates noise at source, while noise barriers/noise enclosures are mitigation measures that block noise propagation. Both are direct noise mitigation measures that may be adopted on roads under road works projects. Acoustic windows/balconies, which provide noise reduction while maintaining ventilation, are not direct noise mitigation measures adopted on roads and generally do not fall within the funding scope of road works projects. Window insulation refers to single frame double pane windows, which shall be accompanied by air-conditioning systems, and is classified as an indirect noise mitigation measure. Indirect noise mitigation measures will only be considered upon exhaust of direct noise mitigation measures.

(2) According to information provided by the CEDD and the HyD, among the designated projects involving the construction of new major roads that obtained funding approval from FC of LegCo in the past two financial years, the numbers of road projects and the lengths of road sections involving various types of direct noise mitigation measures that may be adopted on roads under road works projects are as follows:
 

Direct Noise Mitigation Measures Adopted on Roads		Year 2024/25	Year 2025/26
Low noise road surfacing	Number of road projects	6	1
	Length of road sections involved (km)	23.3	10.3
Noise barriers/noise enclosures	Number of road projects	6	1
	Length of road sections involved (km)	17.0	4.9

Note: Vehicle speed management is not a noise mitigation measure adopted under road works projects.

(3) to (5) Under the prevailing Environmental Impact Assessment (EIA) system, project proponents would, at the engineering feasibility study and design stages, consider direct noise mitigation measures at source and other practicable direct noise mitigation measures having regard to the actual circumstances of individual projects, with a view to formulating suitable mitigation proposals. In brief, project proponents may, depending on actual circumstances, adopt either an approach of "prioritising noise mitigation at source" or other mitigation options.

     For road works, the Government has in recent years continued to develop, improve and promote noise mitigation measures, including low noise road surfacing and acoustic windows. Acoustic windows have also become increasingly popular. In 2023, the EPD amended the Technical Memorandum on Environmental Impact Assessment Process under the EIAO to include noise mitigation measures such as acoustic windows and acoustic balconies as direct mitigation methods that have to be considered. This enables project proponents to formulate more cost-effective and practicable mitigation proposals having regard to the actual circumstances of their projects, for example, by laying low noise road surfacing on new roads, together with the adoption of noise mitigation measures such as acoustic windows or acoustic balconies in planned residential buildings, to address traffic noise problems and reduce the need for constructing noise barriers. The amendment has enhanced the flexibility of noise assessment and helps reduce project costs.

     At present, paving low noise road surfacing material on roads constructed in new development areas, together with the adoption of noise mitigation measures such as acoustic windows or acoustic balconies at planned residential buildings, is generally adequate to address the relevant traffic noise impacts. Therefore, the need for project proponents to construct noise barriers/noise enclosures for new roads has significantly decreased, leading to substantial reduction in overall road construction costs. For example, the abovementioned low noise road surfacing and acoustic windows/balconies were adopted as direct noise mitigation measures in the EIA for the San Tin/Lok Ma Chau Development Node project in 2024 and the EIA for Road D1 in the Development at Ngau Tam Mei Area in 2025, successfully eliminating about 2.2 kilometres of noise enclosures. While significantly reducing project costs, this approach can still effectively mitigate the noise impacts of the projects on nearby residents.

     In addition, the EPD has incorporated smart noise assessment and spatial analysis tools into the Hong Kong Environmental Database, enabling project proponents to enhance their project design and formulate suitable noise mitigation proposals at an early stage.

     The expenditure on the repair, maintenance and replacement of direct noise mitigation measures adopted on roads under road works projects varies depending on the actual circumstances and completion dates of the individual projects. According to information provided by the CEDD and the HyD, the expenditure on replacement works for relevant noise mitigation measures completed in the past five years (2021 to 2025) due to damage caused by traffic accidents and other reasons in the past two financial years, is as follows:
 

	Year 2024/25 Expenditure ($ million)	Year 2025/26 Expenditure ($ million)
Expenditure on replacement works of noise barriers and noise enclosures	1.5	4.3

Note: The HyD regularly inspects public roads, structures and associated facilities under its purview. If wear and tear is found on noise barriers, noise enclosures or related facilities, the HyD will arrange contractors to carry out the necessary repair works in a timely manner. Such works form part of routine maintenance of road structures. The HyD does not keep a separate breakdown of routine repair and maintenance expenditure for individual structures, such as noise barriers, noise enclosures and related facilities.

Ends/Wednesday, May 20, 2026
Issued at HKT 11:15

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