Roads Funding Chris Grayling To ask the Secretary of State for Transport what the average cost was of constructing a mile of (a) motorway, (b) additional lane of motorway and (c) trunk road in the latest period for which figures are available. Dr. Ladyman The average cost for constructing a mile of motorway is £29.9 million. I refer the hon. Member to my previous answer of 13 June 2006, Official Report, column 1116W, for the cost of an additional kilometre of lane of motorway in the period of 2005-06 as the latest available. The equivalent rate per mile is £10 million. The average cost for trunk roads of constructing a mile of dual carriageway is £16.2 million and single carriageway £10.6 million.