If you think gas is expensive, try filling a 300-gallon tank with diesel every time you pull up to the pump.

"When I drive down the road from Charlotte to Charleston I keep an eye open for the best price," truck driver Kevin Tackett said while filling up at Love's Truck Plaza on Sutton Road last Friday. "It's become an exercise in futility. They're all ridiculous. There is no best price."

Tackett drives a rig for Charlotte-based Poseidon Enterprises. Fortunately for him, Poseidon pays for his fuel, which has jumped more than a dollar in price since the end of last year.

"These independent guys, that own their own truck, are the ones that are really hurting," Tackett said.

Fort Mill resident Ames Deese is one of those independent drivers. Last year he spent $50,720 on 18,829 gallons of diesel, he said. With seven months left in 2008, he's already spent $19,137 on 5,415 gallons. Less than two weeks ago he watched as the price of diesel jumped 24 cents overnight from Thursday, May 8, to Friday, May 9. He bought 145 gallons - half a tank - on May 8. If he had filled up the next morning, it would have cost him another $34.80.

"I expect to spend $65,000 this year, even running less miles than last year," Deese said.

Deese used to drive all over the country. Late last year he switched to a local route, from Chester to McBee.

"I went from running like a pinball to running like a yo-yo," Deese said.

A trucker since 1977, Deese bought his own rig and flatbed trailer in 2002. He works with Charlotte-based National Freight Transportation to secure loads, but he's on his own for fuel.

"Last year, $2.69 a gallon was the average price," he said. "My first purchase this year was on Jan. 2. It was 110 gallons for $349.63 at $3.179 per gallon. It's up over a dollar since Jan. 2."

It doesn't help that even the most fuel efficient 18-wheelers only get six miles to the gallon, according to Bernie Faulk, president of National Freight Transportation.

"The shippers want you to haul their stuff as cheap as you can," Faulk said. "So the shippers want the cheapest rate and the truckers are paying $4.25 a gallon. It's very tough."

It is not uncommon for Faulk's drivers to pour $1,000 worth of diesel into their tanks at each fill-up. The trucks average 40 tons (80,000 pounds) with a full load, which is the heaviest they are allowed to be under state and federal laws. National Freight operates 15 trucks that run across the eastern half of the U.S.

"We don't go out west anymore," Faulk said. "It's too expensive."

But it's not just fuel costs that are going up. Petroleum works its way into nearly every aspect of the trucking industry. The engine on a big rig holds 40 to 45 quarts of petroleum-based motor oil. And trucking companies and independent operators pay $250 to $350 per petroleum-based tire, Faulk said.

According to U.S. Department of Energy statistics, the average price of diesel in the East Coast region during the third week of May 2007 was $2.758 per gallon; Last week, it was selling for $4.319 per gallon at Love's. Despite the high prices, Deese said he is against the proposed gas tax holiday proposed by U.S. Senators John McCain (R-Ariz.) and Hillary Clinton (D-N.Y.), who are both running for president. Revenue from that tax pays for highway upkeep. He worries it would harm road maintenance and lead to more states turning public thoroughfares over to private companies as toll roads.

"The Pennsylvania Turnpike costs .34 cents per mile, just from tolls," Deese said. "Plus, we have to pay fuel taxes on all miles you run in Pennsylvania."

Indiana just handed one of its toll roads over to a consortium of Spanish and Australian businesses on a 99-year lease. Chicago just turned one of its toll roads over to private hands on a 75-year lease.

"That's taking money Americans pay to run on the roads and shipping it across the ocean," he said. "The fuel tax give you more bang for your buck than a toll for maintenance."