§ Mrs. MayTo ask the Secretary of State for Transport, Local Government and the Regions what research his Department has undertaken into the relative effectiveness of reducing noise levels of(a) porous asphalt and (b) this surface coating road surfaces. [16597]
§ Mr. ByersMy Department has researched the relative effectiveness of porous asphalt in reducing traffic noise levels from those generated by a conventional motorway asphalt surface for nearly 20 years. The specification for porous asphalt was developed using research into ways of increasing its durability, which was inevitably reduced by its porosity. One of the issues emerging from the longer-term research into porous asphalt has been the tendency for its performance to reduce as the pores become clogged.
Thin surface coating road surfaces have been researched since these surfacings first became available in the early 1990s. A wide range of proprietary materials covered by this description has been subjected to a range of tests developed by the British Board of Agreement under the Highway Authorities Product Approval Scheme. The test of relative acoustic performance included within this scheme was developed from the procedure used in the research programme.