State Sen. Scott Richardson wants to increase the taxes South Carolina drivers pay on gasoline and other motor fuels to pay for improved roads throughout the state.

Richardson, R-Hilton Head Island, is pushing two different ways to raise the money: one that would add a nickel to the per-gallon tax and a separate idea to charge a sales tax on fuels.

"This is something the public understands," he said. "You're collecting a tax on the people that are using the facility. If you want to drive on safe roads and well-maintained roads, then you're not going to have a problem with paying additional taxes if that's what it takes to do it."

South Carolina's existing tax of 16 cents per gallon hasn't changed since 1987. Richardson would raise that to 21 cents per gallon, while also tying the tax to the inflation rate.

His sales tax idea would charge petroleum distributors a franchise fee of 5 percent. Richardson acknowledged that while the franchise fee would be assessed on petroleum distributors, the costs almost certainly would be passed on to consumers at the pump. That would mean paying an extra 5 cents for every dollar you spend on gas.

Raising the per-gallon tax by 5 cents would raise about $160 million a year, while the 5 percent sales tax would raise about $285 million, Richardson estimates.

The state Department of Transportation has long wanted more money to improve the state's primary and secondary highways. An effort in 2003 to increase the tax by 5 cents a gallon failed after legislative leaders cut off discussion, citing budget problems and a competing attempt to increase the state tax on cigarettes.

Michael Covington, director of government affairs for the Transportation Department, said 90 percent of recurring state highway funding comes from the gas tax. The rest comes from car registration, permitting fees and other smaller sources.

Last year, the Department of Transportation Commission voted to encourage the General Assembly to create another transportation funding source. The commission suggested charging a fee based on the number of axles on the vehicle.

"The commissioners thought axle-fee was common sense -- (based on the) more wear and tear you put on the road," Covington said.

But either of Richardson's proposals to raise money for transportation would help the state's highways, Covington said.

Many legislators have said they would oppose a tax increase this year, but Covington said Richardson's proposals will at least help start a conversation.

Other lawmakers have voiced support for separate legislation that would take about $128 million of money collected through the gasoline tax and other vehicle registration fees that now goes to other purposes and redirect it to highway spending.

But even groups whose members consume massive amounts of motor fuels, such as the South Carolina Trucking Association, are supporting an increase in the fuel tax.

"We recognize that it's been a very long time since the (Department of Transportation) and our road system has been given any additional revenue for maintenance and system expansion purposes," said Rick Todd, the trucking association's executive director. "We, like all highway users, are more than willing to support reasonable increases in funding for the Department of Transportation."

That means the truckers would support the nickel increase in the gas tax but haven't yet decided about Richardson's proposal to charge the sales tax on fuel.

Richardson vowed to keep bringing the proposals to the table until lawmakers approve more money for transportation.

"I'm going to be everyone's worst nightmare until it gets done," he said.