M40 (Hansard, 17 June 1994)

§ Mr. Key

These questions relate to operational matters of the Highway Agency. I have asked the chief executive, Mr. Lawrie Haynes, to write to my hon. Friend.

Letter from Lawrie Haynes to Mr. David Lidington, dated 16 June 1994: The Minister for Roads and Traffic, Mr. Robert Key, has asked me to write to you in reply to your recent six Parliamentary Questions about the forthcoming resurfacing of the M40 between Junction 5 (Stokenchurch) and Adwell near Postcombe. It might be helpful if I were first to fill in some of the background. The obligations placed on the Department of Transport to deal with noise intrusion relate only to where the Department acts in the manner of a developer in providing a new road or in substantially altering an existing one. It follows that the Agency can only undertake maintenance of existing roads for genuine maintenance reasons and, trials apart, then only in the most cost-effective manner. As porous asphalt (PA) is known to be more costly to construct and maintain, normally its use can only be justified at present for new construction works where these higher costs can be offset by savings in the costs of noise mitigation measures which would be otherwise incurred. There are, of course, no similar offsetting saings to be had in the case of maintenance works. PA is relatively new material which needs to be tested before more wide scale use. The 4½ mile section of the M40 which is now to be re-surfaced was built in the early 1970s and has a jointed concrete carriageway. As we have no experience of overlaying PA on roads constructed in this way, we are taking the opportunity presented by the maintenance to carry out a trial over the 2 mile stretch between Junction 6 and Adwell. This length is quite adequate for trial purposes. The trial is not, therefore, specifically aimed at noise reduction but it is designed to get some of the technical information you seek and more. Interim results are unlikely to be available for at least 18 months. The answers which I give below to your questions should, therefore, be taken as very provisional. 668W Tenders for the maintenance contract are still being evaluated. Early indications are that the additional construction costs of resurfacing with PA the length between Junction 6 (Lewknor) and Adwell (near Postcombe) will be in the order of £800,000. Using the tenders for that length as the measure, the additional construction costs of using PA on the length between Junctions 5 and 6 would be in the order of £1M. I cannot yet quantify additional maintenance costs. The Agency has had no reason to undertake accurate assessments of the number of properties close to the M40 in these areas. However, a count made from available plans suggests the numbers may be as follows:

	Number of Properties
Location	100m	200m	300m
Junctions 5–6	30	51	68
Junction 6—Adwell	2	14	56

In 1993 the average traffic flow between Junctions 6 and 7 was 71,200 vehicles per day. There is not a traffic counter between Junctions 5 and 6, but flows there are likely to be broadly similar to the adjoining stretch of motorway.

As the maintenance work is not aimed at noise reduction, we have not carried out any assessment of existing noise levels over the Junctions 5 to 6 length and have not estimated the reductions which might result from the re-surfacing of that length in hot rolled asphalt (HRA). It is likely, however, that the perceived noise levels will be less given the elimination of joints in the present surface.

'Before and after' measurements of noise will be taken at selected sites to quantify the noise reducing properties of PA on the Junction 6 (Lewknor) to Adwell length. The results will not be available for some time. No estimates have been made.