Local automobile dealers are hoping for a boost in sales with the start of a federal program giving owners of older cars a voucher toward the purchase of a new car.

"Cash for Clunkers" starts in earnest tomorrow as car dealerships await the announcement of the official rules for the federal program, in effect since July 1.

The program gives $3,500 or $4,500 trade-in vouchers to customers who bring in their old vehicles to be junked. To qualify, cars must be 10 to 25 years old, get 18 miles per gallon or less and have been insured by the owner for at least a year.

Dealers encourage customers to visit http://www.cars.gov to see if their vehicle qualifies.

The program is expected to improve sales for an industry that's been dashed by the economy — sales in Hawai'i slipped by 31.5 percent in the first six months of 2009 compared with last year.

Auto Outlook Inc., an independent auto market research firm, estimates the program will generate about 1,100 new vehicle sales this year in Hawai'i.

"We're expecting an increase in sales of about 2 to 5 percent," said John Kato, senior sales manager at Cutter Pontiac Buick GMC in Waipahu.

Two customers have already come down to Cutter in Waipahu to trade in their old SUVs for a truck and a Mazda3, despite no advertising from Cutter about the program.

Kato said both car sales are pending the announcement of the program's rules tomorrow.

"Cash for Clunkers," or the Consumer Assistance to Recycle and Save Act of 2009, started on July 1, but a lack of details about how it will work has caused a little uncertainty at dealerships.

Rick Ching, Servco Auto Centers executive vice president, said while Servco is not yet accepting trade-ins, people should come in.

"If people think they qualify, we encourage them to come in and start the process of deciding what car you want and what qualifies for the gas mileage to get the full amount. There is some concern that the $1 billion could run out, even before the program is slated," he said.

Most people who qualify will get at least a $3,500 voucher. Those who buy a new vehicle that gets 10 mpg or more than their clunker will receive $4,500.

Damien J.K. Farias, general manager of Maui Toyota, said with the program's current budget, he wouldn't be surprised if it is depleted in the first month and a half.

"It was $4 billion initially," Farias said of the bill's budget, "but when Obama got involved and the economy the way it is, it was trimmed back to $1 billion.

"You look at the number of dealers involved and the amount of car costs and it really dilutes the program. (A dealer) will sell around a dozen or so before the money will be gone."

Don Mann, used-car manager for Windward Dodge Chrysler Jeep, just wants to know what to do with the cars after he accepts them. Dealers are required to provide proof of disposal of the clunkers at approved scrap-metal yards.

So far, no scrap yards have been announced for dealers to take the cars to, nor is there any word on how to stay below the government's $1 billion allotment.

"It's a wait-and-see game right now," Mann said. "The government only has so much money (for) the program, so if you sell a car and it goes over how much they had, you're (out of luck)."

Bill Mickelson, general manager at King Windward Nissan, said the government has made the program more complicated than it needs to be, but he believes the program can only improve business whether people have clunkers or not.

Dave Rolf, executive director for Hawaii Automobile Dealers Association, was optimistic and complimented the speed of implementing the program since the act was signed on June 24.

"I don't think in all my years I have seen a program come together this fast," Rolf said. "It's a great compliment to the people in federal government. When you look at how many moving parts are in a car and then how many cars there are, and then how many people are in America; and to get a program moving in 30 days?

"That's a lot of moving parts."