NASHVILLE (AP) - State Attorney General Herbert Slatery says a proposal to boost Tennessee's road fund by raising taxes and fees on out-of-state trucks would be unconstitutional.

The Commercial Appeal reports (http://bit.ly/1Ht8oPR) that the bill sponsored by Sen. Paul Bailey of Sparta and fellow Republican Rep. Cameron Sexton of Crossville would violate both the commerce and equal protection clauses of the U.S. Constitution.

The measure would raise the diesel fuel tax by 13 cents a gallon for commercial motor carriers and also require heavy trucks to pay 2.85 cents per mile as part of a new "highway maintenance fee."

Where Slatery says the measure runs afoul of the constitution is in a provision to allow Tennessee-based motor carriers to recoup those surcharges in the form of credits in their corporate taxes.