§ Mr. David Youngasked the Secretary of State for the Environment (1) what have been the total maintenance costs of six-lane motorways in the United Kingdom for each of the last five years; and if he can apportion the costs of wear and tear between (a) buses, (b) cars and (c) heavy lorries;
646W(2) what have been the maintenance and repair costs for the M6 in each year since its construction; and if he can apportion the wear and tear between vehicles of different types, namely, private cars, heavy lorries and buses.
§ Mr. MarksThe information sought in both Questions is not available except at disproportionate cost. It is possible to give the total cost of maintaining all motorways in England over the last five years as follows:
Year Expenditure (Outturn figure in year concerned) £m. 1971–72 … … … 4.6 1972–73 … … … 5.7 1973–74 … … … 6.0 1974–75 … … … 9.0 1975–76 … … … 15.7 Generally, the structural damaging effect caused by different vehicles using a motorway is proportional to the fourth power of the axle weight. This gives relative damaging effects for buses, cars and heavy lorries on motorways generally in the ratio of approximately 60:1:14,000.