Idaho Gov. C.L. "Butch" Otter says the state could raise money for needed transportation projects by charging drivers for how much they drive.

Otter described the proposal to about 150 people attending an Idaho Falls City Club Forum on Monday, the Post Register reported.

"I believe in user-based pay," Otter said.

Under the plan, people would disclose their vehicle's mileage when they register the vehicle. Each year, state officials would subtract the current year's mileage from the previous year's mileage and charge the driver accordingly. The more mileage a driver reports, the more he or she would pay.

Idaho's roads and bridges need improvement, Otter said, and the state Transportation Department needs more money to make those improvements, even if it means raising taxes.

Transportation Department officials have said the state faces an annual $240 million backlog in road maintenance funding, though some lawmakers have questioned that number.

"We do need more money, we do need more help," Otter said.

So far, discussions on how to tackle the shortfall have focused on either increasing registration fees or raising Idaho's gas tax, which has been 25 cents per gallon since 1996.

During the last legislative session, state lawmakers balked at Otter's proposal to increase registration fees to $150 for all vehicles. They are currently based on the car's model year and range from $24 to $48.

Last month, amid worries about the economy and federal spending levels, the Idaho Transportation Board voted to cut millions of dollars from what it wants the state to borrow in 2009 to pay for improving and repairing state roads.

The board decided to ask lawmakers to approve $125 million in new debt, instead of the $229 million it originally planned. The debt is financed with bonds backed by federal highway payments.

Also last month, Otter told top state administrators and department heads to find ways to cut their 2009 budgets to offset a nearly 6 percent projected shortfall in state revenue.

Earlier this year, the Senate Transportation Committee authorized a comprehensive audit of the Transportation Department to identify spending habits and identify potential savings. Lawmakers have said they want to see the results of that audit before passing any fee or tax increases.

Otter said fixing roads across the state is of the utmost importance, for both the well-being of Idaho's residents and its economy.

"It's going to be tough to do, but it's necessary to do," he said.