To ask the Scottish Executive what the estimated cost is of the road equivalent tariff pilot scheme announced by the Minister for Transport, Infrastructure and Climate Change on 26 February 2008. The budget allocation for the road equivalent tariff (RET) study and pilot in years (a) 2008-09, (b) 2009-10 and (c) 2009-10 is £5 million, £7.5 million and £10 m...