Mr Scott (Lib Dem) has launched a consultation on the country's transport policy, which criticises over half of councils for not spending their full allocation on highway maintenance. Some have been using less than half of it.
'Maintaining the local road network, as a key national asset, must be a priority and we are interested in views on how we might ensure that local authorities fully spend the allocation,' the consultation says.
'This could include, for example, ringfencing of the allocation.'
Road traffic volumes were expected to grow by 23% in the decade to 2011, and surface transport accounted for 19% of carbon dioxide emissions.
The consultation also signals a potential move to road pricing for Scotland. Mr Scott said car drivers paid an artificially low price for transport, which did not include air pollution, noise and congestion.