State governments, facing budget disaster, have mined other revenue sources, including tolls.

ECONOMIST: Repairing America's roads

It recommends moving towards a nationwide system of road charging, including road tolls, to account for this loss of revenue.

BBC: Compelling case for UK road charging, IFS study says

Bills including the abolition of bridge tolls, scrapping the graduate endowment and safeguarding rural schools were set out to the Scottish Parliament.

BBC: Salmond outlines government plans