More children who weren't buckled into safety seats are dying in Virginia car crashes, and officials are worried about the trend as summer traffic increases.

"What we're seeing is the usage of child safety seats going down," said Bill Dennis of the Virginia Department of Motor Vehicles. "It used to be around 80 percent, and now it's 63 percent."

Through July 22 of this year, nine children under age 4 who were not in safety seats, as required by a 1983 state law, have died in traffic accidents. During all of 1989, 11 children who weren't in safety seats died.

"If you look at it statistically, it's an alarming figure," Dennis said.

"In the first six months of the year, we reached {almost} what the figure had been for all of 1989, and we're still looking at heavy summer and Labor Day traffic."

In Maryland through May 31 this year, two children who were not in safety seats have been killed in accidents. In 1989, three children were killed. In the District of Columbia, no children died in car accidents in 1989 or so far this year.

Jan Buckner, a psychologist who works with Virginia's Crash Investigation Team and is studying the problem, said parents' ignorance may be a chief cause of the rising death rate.

"This law went into effect in 1983," Buckner said. "My theory is that the parents who had small children then no longer have to use the seats, so we have a whole new generation of parents who may not even know this is a law."

Buckner said the accidents can't be categorized.

"They've happened all over the state," she said. "They happen on urban roads, on secondary roads and on primary roads. Most of these people were close to home and were going short distances."

Three of the deaths this year occurred on interstate highways. In 1989, there were two such child fatalities.

While all states and the District require that children be restrained in safety seats or seat belts, 336 children under age 4 who weren't buckled up died in 1989, according to the National Highway Transportation Safety Administration. In 1988, the number was 341.

Safety officials estimate that the seats, when properly used, prevent 71 percent of the deaths that might have occurred without their use.

Nationwide, 163 children in safety seats died in accidents in 1989. The number for 1988 was 166.

Even when seats are used, they often are used improperly, Dennis said. Some parents put the seat in the car and don't buckle it in, or they don't strap the child in.

"Either they aren't using it or they aren't using it right," Dennis said. "This is a real law in Virginia. You can be stopped for not having a child in a safety seat, you can be fined, you can have driving points put on your license."

Virginians unable to afford a safety seat, which costs $40 to $70, can apply to the state for a free one by calling the Virginia Department of Motor Vehicles at 1-800-533-1892.