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Government Press Release on 24/12/06

Green noise barriers to go on trial

Plants can soften the appearance of noise barriers and improve the streetscape, Highways Department Chief Engineer Chow Chun-wah says. Special panels will be put on trial on two road sections in Kwun Tong and Tsuen Wan where noise-barrier retrofitting will begin in 2007.

Noise barriers and enclosures are often installed to protect residents from traffic noise. While they mitigate noise, they also have a visual impact. In this regard, a study was launched early this year to explore the greening and aesthetic design of noise barriers.


To alert our feathered friends, falcon stickers (right) have been put on the transparent noise barrier along Kam Tin Bypass to make the panel visible to birds.

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On other greening measures, such as concrete panels with climbers, the engineering expert said the public prefer transparent panels since concrete ones may block views and light.

Apart from the acoustic, aesthetic and greening aspects, engineers must also take into account the safety of our feathered friends, especially when designing noise barriers in areas with high bird density or in rural areas.

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Barriers made visible

"With the advice of the Agriculture, Fisheries & Conservation Department, we have put falcon stickers on a section of transparent noise barriers along Kam Tin Bypass since June, to make the barriers visible to birds, following reports that bird carcasses were found," Mr Chow said.

Local and overseas experiences have shown that falcon stickers can cut the number of birds who fly blindly into the transparent barriers. The AFCD's initial assessment found the trial on Kam Tin Bypass worked well, with only one dead bird found in the two-month observation period.

In the same period, 20 bird carcasses were found along the section where no falcon stickers were posted.

To confirm the stickers' effectiveness, falcon stickers will be put on another section of transparent noise barrier along Kam Tin Bypass in early 2007.

Mr Chow noted so far there are no dead-bird reports for other roads fitted with transparent noise barriers.

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24/12/06 政府新聞稿

兩路段引入綠化隔音牆

路政署的研究發現，以透明物料建造隔音屏障，可減低侷促的感覺，但若情況許可，可考慮加添綠化元素，如採用綠化隔音牆、附以攀爬植物的混凝土隔音屏障、土堤，以及綠化隔音罩頂部。

將軍澳道近翠屏南邨和青荃橋荃灣段引道，將試行引入綠化隔音牆，預計2009 - 10年完成。

為提高雀鳥的警覺，錦田繞道的透明隔音屏障已貼上猛禽的圖案。

錦田繞道的1段透明隔音屏障則已貼上猛禽圖案（右圖），提高雀鳥的警覺。

... 加上區議會和居民的意見大多傾向採用透明的隔音屏障，故較多採用透明的隔音屏障。

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隔音屏障的設計，除了能發揮屏障的功能，以及具美化和綠化的效果，若裝設的地點位處鄉郊，或是雀鳥經常途經或聚集，設計便也要顧及保護生態的元素。

     周進華表示，在收到意見指出，在錦田繞道近高埔村的透明隔音屏障附近發現雀鳥屍體後，便根據漁農自然護理署的建議，6月在1段透明隔音屏障貼上獵鷹圖案，以測試這能否減低雀鳥撞向透明隔音屏障的成效。

猛禽圖案試驗理想

     根據本地和海外的經驗，猛禽圖案能令其他雀鳥更為警覺，並察覺到透明隔音屏障的存在，以減低雀鳥撞向透明隔音屏障的機會。

     漁護署的初步評估認為，試驗的效果理想。在兩個月的試驗觀察期內，貼上獵鷹圖案的屏障下，只錄得1隻死雀，較同一地段沒貼有獵鷹圖案的屏障下錄得的20隻死雀數目明顯為低。

     路政署明年年初在上址另一段透明隔音屏障貼上獵鷹圖案，以便漁護署進一步研究這些圖案的成效。

    周進華指出，除錦田繞道外，暫時未收到報告指其他路段的透明隔音屏障下發現死鳥。

     然而，若有迹象顯示透明隔音屏障對雀鳥構成危險，漁護署和路政署將研究是否需要貼上獵鷹圖案及其可行性。

     路政署已有作業指引，要求工程師在設計階段，考慮預防雀鳥撞向透明隔音屏障的設計。有關作業指引的詳情，可瀏覽這裡。

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Link given in the Chinese version of the press release.

PRACTICE NOTES NO. BSTR/PN/003 - Revision B
Noise Barriers with Transparent Panels
Bridges and Structures Division October 2006


3. Design Considerations

Apart from the noise mitigation requirement for the noise barrier, the designer shall also consider, inter alia, :-
(i) Cost effectiveness
(ii) Safety and fire resistance
(iii) Aesthetics
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(ix) Bird collision
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3.9 Bird collision

There are reported cases where birds collide onto the transparent noise barrier panels causing bird mortality. As the panels are either transparent which appears invisible to birds or reflective that mirrors the facing landscape, birds are unable to recognize them as physical barriers. Having considered the bird collision problem, the Director of Agriculture, Fisheries and Conservation (DAFC) recommended that transparent materials should be avoided as far as possible in the design of noise barrier in areas with high bird density or for roads that cut across rural areas.

To address the bird collision problem, designers should consider bird collision measures during the design stage. It has been a standard practice in Hong Kong to provide transparent noise barrier panels with either tinted materials, embedded opaque stripes or superimposed patterns of thin opaque stripes. However, recent experience suggested that application of tinted materials alone may not be adequate in preventing bird collision and further mitigation measures are needed. In this regard, our department and DAFC are investigating several alternative measures to address the problem. Designers may take note of the investigation and seek DAFC’s advice where necessary.