The methodologies for the Department's inter-urban and urban congestion PSA indicators can be found on the DfT website at the following web addresses:
Inter-urban
www.dft.gov.uk/adobepdf/162469/221412/221546/226956/coll_congestiononthestrategicroa/cs r07revisedbaseline.pdf
Urban
www.dft.gov.uk/about/howthedftworks/psa/spending review2004psatargets2
While strategic A-roads in rural areas are included in the inter-urban indicator, there is no separate indicator for rural roads.