Would you rather pay about 40 cents per gallon of gas you buy ? (Right now you’re paying the state 22 cents per gallon.) Or would you try paying 1.5 cents per mile you drive? No pressure, but the answer might determine how the state funds its transportation system.

For now, the Colorado Department of Transportation is spending $750,000 to test the idea, starting with 100 drivers, reports the Denver Business Journal. Drivers don’t have to pay yet. CDOT just wants to know how best to measure the amount they drive.

Whether the idea works or not, the state transportation funding needs some changes. CDOT has made clear that the agency can only maintain our system for the next ten years.

Right now, CDOT gets 61.3 percent of its funding from the federal and state gas tax. But the federal gas tax of 18.4 cents hasn’t risen since 1993; the state tax of 22 cents hasn’t risen since 1991.

As CDOT Executive Director Shailen Bhatt told Colorado Public Radio, “We are investing in our transportation system like it’s 1992.”

Then there’s the fact that we’re using less gas, generally speaking. And plug-in electric cars don’t even use gas. Instead they pay an annual fee, which some researchers argue is inefficient.

Colorado’s not alone in this either. California expects to lose half its fuel tax revenues by 2035 because of better fuel efficiency.

Nor Colorado is not the first state to work with the idea of a road usage fee; Oregon’s been on it for 15 years. There, the drivers who’ve signed up to test the road-usage charge have been those who stand to pay the most — the people with fuel efficient cars.

So what about you? Would you sign up? DBJ reports that CDOT hopes to have a website up in August, then start actual testing in December.