(WEAU) - It is both the veins and arteries of Wisconsin. It carries cars and commerce more than 700 miles from north to south and east to west across Wisconsin.

The interstate system makes up less than 1% of Wisconsin roads but carries 18% of its total traffic.

"It largely gets people to work, gets goods to market, gets manufactured products to market, gets agricultural products to market," said Mark Gottlieb, the Secretary of the Wisconsin Department of Transportation.

But the system that takes us non-stop to places like Madison, Milwaukee or Minneapolis is beginning to show its age. Eight out ten of the main interstate stretches across the state first went up in the 50's and 60's.

"They're reaching the end of their useful life, the pavements and bridges on, they're going to need to be replaced, and that's going to be a costly undertaking," said Gottlieb.

The total bill would be about $26.2 billion dollars over the next few decades to replace and upgrade the system. Right now the gas tax you pay at the pump is what fuels funding for the interstate system. But there is a problem.

"The inherent problem is that as cars become more fuel efficient, it's going to take a higher and higher tax to even raise the same amount of revenue we are now," said Michael Ford, a researcher with the Wisconsin Policy Research Institute.

A recent study suggested adding toll roads in Wisconsin to help fund the state's interstate system. So, we went to Madison to find some answers.

It is a transportation engineer in Florida who proposes fixing the freeways and turning them into tollways. He was hired by the Wisconsin Policy Research Institute to do the study. WPRI is a Madison area non-profit.

Ford says when people hear toll, they think of our neighbors to the south.

"People think of the Chicago area toll roads and that's not what we're talking about," Ford said. "We're talking about open road tolling where you'll essentially have a transponder that you'll pay for in advance load up with money and it will automatically be deducted as you drive on toll roads."

No quarters, dimes or nickels. Cars would pay with a device like the i-Pass Illinois drivers use. Cameras would capture images of the license plates of other cars and trucks.

"That's really one of the strengths of open road tolling, is its essentially a user fee for using the roadways," Ford added.

He says tolling could generate somewhere between $4-$18 billion dollars in 30 years.

Some drivers say they are willing to go the extra mile and pay a little more.

We caught up with several people at the rest stop in Menominee to ask them whether they would want to pay toll fees to use the interstate.

"I suppose there could be advantages to making the frequent drivers who are using those roads contribute to the cost," said Erica Furey, a driver from the Minneapolis area.

"Considering how budgets are tight, maybe it would be a good idea," said Eric Shoen, a driver from the Minneapolis area.

"I don't think we want to discourage anyone coming through our state because of toll roads," said Dan Stebert, a driver from the Wausau area.

Tolling would be something new for Wisconsin.

"Certainly tolling is one thing that a number of states do and a number of states are talking about, it's not something that's been done here in Wisconsin," secretary Gottlieb said.

The State Department of Transportation tells us it has not taken a position on the proposal. So, the tollway idea is still just that. But Michael Ford says it is the solution to a growing problem.

"The further we wait to find a new revenue source to pay for rebuilding our interstate system,the more problems we're gonna have," Ford said. "So it's an idea but it's a pressing idea that I think will get some legislative attention."

But if life support for the interstate system that lets traffic flow through the state involves charging drivers tolls, it would mean lawmakers proposing and approving it, and the governor signing it into law first.

To read the full report on the tolling recommendation, click here.