The Wisconsin Senate is scheduled to vote on a constitutional amendment that prevents lawmakers from diverting money from the state transportation fund to pay for other items.
The Assembly passed the measure last week with an overwhelming 82-13 vote.
If it clears the Senate on Wednesday, it would then get on the ballot for voter consideration in the November 2014 election.
Republicans authoring the amendment say any money the state collects through the gas tax, fees imposed on driver's licenses and titling vehicles must go to the transportation fund and could not be used for any other program.
Former Democratic Gov. Jim Doyle diverted $1.3 billion from the fund to pay for schools and other expenses.