For discussion on
28 July 1999
Legislative Council Panel on Transport
Design Standards and Noise Mitigation Measures of Roads
This paper informs Members of the design standards and features of roads and the provision of traffic noise mitigation measures.
ROAD TRAFFIC ACCIDENTS STATISTICS ON EXPRESSWAYS
2. The traffic accidents statistics on major high speed roads, i.e. expressways, compiled for the past three and a half years at Annex A show that the accident rates on these roads are far below the average accident rate for all roads in the territory. Annex B shows that the trend of road traffic accident in the past ten years is declining.
3. In comparison with other major overseas cities, Annex C shows that Hong Kong's road traffic fatality rate is lower than Singapore in Asia, Toronto in North America and Frankfurt in Europe, but higher than Tokyo, Hamburg and Stockholm.
4. For traffic congestion on expressways arising from emergency situation, the Police will take charge on site and take appropriate actions including temporary traffic diversion and other management measures with a view to bringing, as soon as possible, the traffic back to normal. As there is only one road link to the new airport, we have developed a set of contingency traffic and transport plans to deal with incidents which might occur on the Tsing Ma Bridge and North Lantau Highway. (We briefed Members on these contingency plans in April 1997.) This would ensure that any disruption of traffic and transport services to the new airport could be kept to the absolute minimum. Similarly, we also have contingency plans for the closure of Tuen Mun Road. If necessary, we would seek the assistance of Government Flying Services for the use of helicopter to airlift any seriously injured or patients who might be affected by the traffic congestion to hospitals for treatment.
DESIGN STANDARDS AND FEATURES OF ROADS
5. The planning and design of roads in Hong Kong have to comply with Transport Department's Transport Planning & Design Manuals (TPDM), Highways Department's Structures Design Manual for Highways and Railways (SDM) and Pavement Design Manual (PDM), and the relevant Technical Memorandum issued under the Environmental Impact Assessment Ordinance (EIAO).
6. TPDM covers generally standards for the geometrical design of highway (e.g. carriageway widths, pavement widths, gradients, sight distance and turning radii), traffic signs and road marking (e.g. regulatory signs, direction signs, carriageway markings), traffic management measures (e.g. one way streets & gyratory systems, bus priority), traffic light signal and safety matters (accident investigation and prevention) etc. SDM and PDM cover the structural aspects of road construction details and road furniture including safety barriers and railings (e.g. design of concrete bridge, recommendations for materials and workmanship, road pavement thickness and parapets etc). The relevant Technical Memorandum issued under the EIAO stipulates that traffic noise limits should not be exceeded (e.g. 70 dB(A) for domestic premises and 65 dB(A) for educational institutions).
7. The above design standards are generally in line with those adopted in major overseas developed countries. We have always been keeping a close watch on design standards and safety features developed in overseas countries and shall further improve our standards having regard to the latest developments and technologies. For example, a modular crash cushion barrier was installed in mid April 1998 at the junction of Tuen Mun Road north bound and Sham Tseng Interchange. This type of barrier systems have been subjected to extensive testing overseas and have been used in a number of western countries. It is considered to be a technically sound system as replacement of the existing end details at vulnerable locations which would help alleviate the damage to errant vehicles crashing directly onto the concrete barrier beam end at the diverge point. Observations in the last 12 months at the site in Tuen Mun Road have shown that the product is suitable for use under tropical climate. A few more sections of the same system will be installed at Tsing Ma Bridge and Hung Hom Bypass to further monitor its site adaptability and geometry constraints.
MITIGATION OF TRAFFIC NOISE FROM ROADS
8. A paper on the policy of mitigation of traffic noise from roads was presented to LegCo Panel on Planning, Lands and Works on 10 June 1999. A copy of the paper is at Annex D.
9. In brief, an environmental impact assessment (EIA) has to be carried out for each new road, major extension or improvements to existing road project to assess and evaluate the environmental impact of the proposed project on the environment. This assessment covers also the noise impact on both the existing and planned sensitive uses including residential developments and schools, and to propose and implement practicable mitigation measures to be applied on roads to abate the traffic noise impacts.
10. All practicable direct technical measures on the new roads on major extensions are required to be implemented before any measures on sensitive receivers are to be considered. Direct noise mitigation measures include noise barriers, enclosures and low noise surfacing.
11. At present, we do not require the retrofitting of direct mitigation measures such as roadside barriers or enclosures to redress traffic noise impacts from existing roads.
12. The Administration is now reviewing the findings of a territory-wide study commissioned by the Environmental Protection Department on the technical feasibility of retrofitting noise barriers and enclosures on existing roads. A programme will then be formulated to retrofit traffic noise mitigation measures to suitable existing roads.
13. Members are requested to note the contents of this paper.