The math is pretty easy for Solon Township resident Jack Freeman, who in 2000 started an independent trucking company with Barry Dunklow of Lake Leelanau.

He charged $2.50 a mile to haul a refrigerated load in his first year, and now charges $3 a mile.

Diesel fuel cost $1.10 a gallon when he started. In recent weeks, diesel prices have soared to record highs, well above $4 per gallon.

Somewhere between the charge he feels his customers can bear and the cost for fuel, lies his profits.

Make that his former profits.

“How much is that gallon of ice cream worth before people don’t pay for it?” he asked, referring to his largest contract with an ice cream manufacturer in Ludington.

“I should be getting a new truck, but I don’t know how this industry is going to shake out in the next few years,” said Freeman.

His 1999 Peterbuilt has 1.3 million miles, and banks have tightened their credit qualifications for the $110,000 to $150,000 loans needed to buy new rigs.

While the high price of unleaded gasoline directly affects most motorists — the average reached $3.33 a gallon in the Traverse City area earlier this week, according to a website maintained by AAA-Michigan — it’s diesel fuel that drives the American economy.

Or perhaps sinks the economy, which appears in or nearing a recession. The American Trucking Association is asking Congress to declare a state of emergency because of the price of diesel.

Jim Rink is spokesman for AAA-Michigan, and a graduate of Suttons Bay. He said the diesel industry is blaming several factors on the high price of fuel starting with crude oil, which was selling for about $80 per barrel in October but reached a high of $111 a barrel Monday.

Other factors heard by Rink include:

• A cold spring has taken some oil off the market to heat homes in the Northeast;

• A switch to an ultra low sulphur mix required by the EPA last year has yet to work through the market;

• And demand on a global scale for diesel fuel has reached record highs. “They are having shortages in China,” said Rink.

Like many consumers, however, Rink is a skeptic. “I’m not satisfied totally they are the right reasons,” he said.

The Traverse City market appears in the middle of diesel prices charged across Michigan, Rink added. The average price yesterday in Traverse City was $4.20 per gallon, identical to the Flint Area and two cents cheaper than in Detroit.

The lowest prices were found in Grand Rapids at an average of $4.14 per gallon.

The sudden jump in diesel prices left some commercial users, including farmers, unprepared. Average diesel prices in Michigan were “just” $3.51 per gallon one month ago.

Solon Township farmer Keith Parker said he paid about $2.50 per gallon to fill his on-site tank a year ago; he expects the price to come in at about $3.75 per gallon today. Farmers often buy and store their own diesel fuel, avoiding per-gallon road taxes charged at retail pumps.

The problem: His storage tank is empty. Parker uses about 4,000 gallons of diesel a season to farm land he owns and leases. “About all of (his farm equipment) runs on diesel — tractors and the combine. It’s going to have an effect,” he said.

And that effect will eventually reach grocery market shelves, Parker believes, as the cost to grow — and perhaps more importantly, to ship — food is bound to go up.

“It hasn’t hit all things yet. It’s going to be a tough one for people who have trouble paying their food bill,” said Parker.

Like Rink, trucker Freeman is skeptical of short-term factors being blamed for the jump in diesel prices. Freeman, whose 3,600 or so miles on the road each week leaves plenty of time for listening to radio programs and talking with other truckers on his CB, believes the problem lies more with a declining U.S. dollar. And that he blames on the loss of America’s manufacturing base.

“It’s not the oil. Everybody is blaming the oil companies because of record profits,” said Freeman. “But the countries making the oil know China is going up and the dollar is going down. Who would you sell your gas to?” he asked.

Regardless of underlying reasons for higher diesel prices, Freeman is dealing with the aftermath with fewer tools than available to large trucking companies that can buy up fuel ahead of price surges and negotiate on a large scale with suppliers for better prices.

He’s the little guy in the equation.

“In the end, everything goes up and we all have to pay for it. In this country, everything is delivered to you by a truck except a baby,” he said.