Does building new roads really create extra traffic? Some new evidence

The debate that expenditure on new or existing roads induces more traffic has intensified during the 1990s in most developed countries. In this paper the controversy is readdressed from a UK perspective, using the method of Granger noncausality. Results indicate that aggregate expenditure on new and existing roads does not induce additional traffic in the Granger sense. Conversely, the results found that traffic Granger causes road expenditure. The importance of these results, along with issues concerning the selection and specification of dynamic models, are discussed.