Michael, There are also some useful UK specific data on generalised and external costs in the ITS / AEA Technology report by Tom Samson et al (2001): surface transport costs and charges UK 1998: http://www.its.leeds.ac.uk/projects/STCC/surface_transport.html Cheers, Christian Christian Brand Research Fellow Transport Studies Unit, Oxford University Centre for the Environment, South Parks Road, Oxford OX1 3QY, UK T: +44 (0)1865 285177 W: www.tsu.ox.ac.uk