§ Lieut. - Colonel Bromley - Davenport
asked the Minister of Transport what modifications have been made to the contract documents for the 26-mile length of the Birmingham-Preston motorway between Preston and Warrington which should make possible a substantial reduction in the cost of the eventual motorway without any reduction in standards; and why these modifications were not incorporated in the contract documents when originally drawn up.
§ Mr. Marples
The vertical alignment of the motorway has been altered in places to reduce to a minimum excavation of material that would be unsuitable for use in embankments; the drainage system has been modified to reduce the amount of expensive piping, whilst still catering fully for the expected rainfall; and the earthworks quantities have been adjusted to take account of a revised assessment of the proportion of excavated material likely to be suitable for use in embankments. Considerable saving is also expected in the cost of additional filling material in the light of later information.
The line of the motorway involves some very difficult engineering problems because of the soil conditions and the climate in Lancashire. While some of the changes which have been made might possibly have been made earlier most of them resulted from the very full investigation of the contract details carried out by my Department, the county council and the Road Research Laboratory which took account of the longer contract period now proposed.