Michigan lawmakers are considering a future-proof way to raise funds for road maintenance. A mileage tax, also known as a road use tax, collects revenue by determining how many miles each driver travels within the state. If implemented, the policy would likely replace or significantly reduce the state gas tax, which currently adds $.30 per gallon. That tax brought in over $1.4 billion for the state last year. If approved, a pilot program would kick off this fall.