Noise Levels from Highways Located Near Residential Areas

Ms Tin Pei Ling asked the Minister for Transport (a) what is being done to minimise the noise transmitted from highways that are built in close proximity to residential areas; (b) how are noise levels measured, sampled and monitored; and (c) in affected areas, how do the measured noise levels compare with international benchmarks for noise pollution.

Mr Lui Tuck Yew: There are several levels of measures to minimise road noise and its impact.

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At the land use planning stage, the Land Transport Authority (LTA), together with the National Environment Agency (NEA) and the Urban Redevelopment Authority (URA), incorporates noise mitigation measures in public housing developments. As far as possible, non-noise sensitive developments such as industries, recreational facilities and parks are located next to expressways and arterial roads to act as noise shields. Developers of residential dwellings must also adhere to URA's building setback requirements to ensure a minimum distance between the facade of buildings and roads.

In addition, LTA uses a special type of road pavement (Open Graded Wearing Course) on expressways to reduce road noise. Greenery is also planted along the sides of expressways and arterial roads to act as visual screens and reduce the transmission of road noise.

NEA regulates noise emission levels from road vehicles. New vehicles, including motorcycles, are required to meet noise emission standards before they are registered for use. In-use vehicles are required to pass noise emission tests during their mandatory periodic inspections for road tax renewal. NEA regularly updates the noise emission standards to keep pace with the advancement in vehicle noise control technology. LTA and the Traffic Police also conduct enforcement blitzes against noisy vehicles on the road.

Measurements of road noise are taken at the facade of residential buildings fronting the road for a period of 1 hour during peak hours. This provides the Equivalent Noise Level for an hour [Leq(1hr)], which is the standard unit used internationally.

NEA's guideline is 67dBA Leq(1hr). Countries such as Hong Kong and Japan have similar noise guidelines ranging from 60 to 70dBA Leq(1hr) depending on the time of the day. In a highly urbanised city like Singapore, we are mindful that our roads may sometimes have to be near residential units. NEA and LTA have thus embarked on a joint study, involving URA, the Housing and Development Board (HDB) and the National Parks Board, to look into the noise levels near expressways, major arterial roads and elevated rail lines, and explore appropriate noise mitigating measures that are applicable to our local context. The study is expected to be completed by the first half of 2012.