Some states are considering a tax on vehicle mileage to counteract the low revenues from gas taxes.

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It's called the vehicle miles-traveled (VMT) tax and Joshua Schank, President of the non-partisan Eno Center for Transportation in Washington D.C., says drivers would be charged based on how many miles they travel. "This can be done through any number of technological means but the idea is that people will be paying more accurately for the roads that they're using than they do currently with the gas tax," Schank says.

Schank says the biggest concern among drivers is one of privacy. He says there are a number of ways to track mileage, some of which are currently being tested in states like Minnesota and Oregon. However, he notes that in reality, vehicles would most likely not have a "black box" in them to track mileage.

Schank says the reasoning for the tax comes from people driving less because of high gas prices and people driving more gas-efficient vehicles. He says higher taxes could lead to an increase in ridership on public transportation, but some of the money collected from the tax would need to go toward public transportation improvements and not just infrastructure improvements.

Indiana is not one of the states currently considering this new approach. However, Indianapolis is already seeing an increase in public transportation ridership. IndyGo CEO Mike Terry says in 2011, they saw about a 10-percent increase in ridership over 2010. He adds that so far this year, they're seeing a 20-percent increase over last year.