§ Lord Moranasked Her Majesty's Government:
What progress is being made with the use of whisper concrete, porous asphalt or other materials to reduce road noise.
§ The Parliamentary Under-Secretary of State Department of Transport (Viscount Goschen)This is an operational matter for the Highways Agency. I have asked the Chief Executive, Mr. Lawrie Haynes, to write to the noble Lord.
Letter to Lord Moran from the Chief Executive of the Highways Agency, Mr. Lawrie Haynes, dated 19 February 1997.
The Parliamentary Under-Secretary of State has asked me to reply to your recent question about progress being made with the use of whisper concrete, porous asphalt and other materials to reduce road noise.
Whisper concrete was included within the agency's specification in 1996 and porous asphalt in 1993. They are now available as options for the construction of trunk roads and are specified where they are technically suitable and where it is cost effective to do so. Whisper concrete has been used on a section of M18 and of the A50. Porous asphalt has been used on sections of M1, M6, M25 and M40, as well as on several all-purpose trunk roads.
Usage has been limited, particularly of porous asphalt because of drawbacks, including higher cost and lower durability. These are being addressed as part of the agency's research programme. Improvements have already been made in durability of porous asphalt, allowing it to be used on more heavily trafficked roads, although the cost is still significantly higher than for conventional materials.
Further research has been carried out into alternative road surfaces which offer reduced noise compared with conventional asphalt and concrete, while providing better value for money than porous surfaces. Work is still progressing, although two materials are already permitted as alternatives to conventional surfaces. It is expected that further materials will emerge from this programme of research.