OLR Report 2014-R-0029 answers the question: Do any states offer tax incentives to encourage trucking companies to ship freight by barge or ferry rather than on state highways?
An online search found no statute meant to encourage trucking companies to ship freight by water rather than by road. However, Virginia offers a tax credit to cargo owners who transport by barge or rail rather than by road.
At least four states, including Georgia, North Carolina, South Carolina, and Virginia, provide indirect incentives for increased port use by offering tax credits to taxpayers who increase the volume of goods they ship through their ports. The laws are described briefly in the report.
OLR Report 2010-R-0305 also includes information about other port-specific tax incentives.
For more information, read the full report.