Road Surfaces (Hansard, 26 October 1994)

§ Mr. Watts

This is an operational matter for the Highways Agency. I have asked the chief executive to write to my hon. Friend.

Letter from Lawrie Haynes to Mr. Richard Page, dated 26 October 1994: The Minister for Railways and Roads, Mr. John Watts MP, has asked me to write to you in reply to your recent Parliamentary Question concerning comparisons between porous asphalt, whisper concrete and conventional road surfaces. We have in hand trials comparing whisper concrete with conventional asphalt and concrete road surfaces. Also, data is available on the comparative performance of porous asphalt and conventional asphalt and concrete road surfaces. From the trials some early indications are available of the noise performance of whisper concrete. These are that for surfaces with equivalent skidding resistance, overall noise levels for whisper concrete are slightly less than for conventional hot rolled asphalt. They are significantly less than for some of the more heavily textured concrete surfaces provided in the past. In the case of porous asphalt as used in the United Kingdom, noise levels are about 5 dB(A) less than for a hot rolled asphalt surface initially, although this difference may reduce to about 3 dB(A) as the pores become clogged. The relative noise performance of porous asphalt compared with concrete surfaces is the same as that given above for hot rolled asphalt where skidding resistance characteristics are similar. However, the texture provided on concrete roads to date has tended to be deeper than the minimum required under the specification with the result that the difference in noise with porous asphalt would be greater in the early life of the road. We have not made any direct comparison of the respective noise performance of porous asphalt and whisper concrete. However, from the data available so far, we can infer the likely relative noise performance of these two surfaces. The picture emerging is that traffic noise levels attributable to whisper concrete are higher than those achieved with porous asphalt.