To protect residents affected by traffic noise from new roads, the Environmental Protection Department liaises with other departments during the planning stage to minimise the impacts. At the start, the alignment of the new road would be carefully considered to minimise the population exposed to traffic noise. A buffer distance may be inserted between the road and the buildings, or screening structures such as roadside barriers may be incorporated where practicable. However, in some cases the constraints of the site may render implementation of direct engineering remedies, barriers or enclosures not practicable. For those cases the standards laid down in the Hong Kong Planning Standards and Guidelines could not be met. Building insulation therefore may be necessary as a last resort. Insulation usually involves upgrading the electrical supply, improving windows and installing new air-conditioning units. This measure is not provided as a matter of general principle and each case will be considered on its merits by the Executive Council. The criteria for building insulation work are described in the Table below.

The figure below shows the accumulated number of dwellings insulated over the years up to 2004 and the total cost involved.