Forty days after the state enacted a law requiring parents who drive with infants to secure them in approved safety seats, Sheila Palombo took her 1-year-old son Joseph for an afternoon drive through Petersburg, Va.

The front passenger door opened as the car rounded a curve on West Lane Street in the city's west end, police said. And the baby, who was sitting on the front seat while his safety chair was in the car's rear seat, tumbled out of the vehicle and onto the highway, according to a state official who investigated the accident. The child later died of his injuries.

Despite increased public awareness about the new safety seat law--and a statewide loan program for those unable to afford the seats--there already have been three infant traffic deaths in Virginia this year. That amounts to an annual rate twice as high as last year's, when nine infants died on Virginia roads.

"I see more and more safety seats in use than I ever saw before," said David O. McAllister, who spent 11 years investigating car accidents involving youngsters for the state's Department of Transportation Safety. "Maybe I'm more sensitized to it. But our phones are ringing off the hook from people asking about the new law and wanting to know where they can get seats."

Still, McAllister and other state officials say they are uncertain whether parents who buy the seats are using them as required by the law, which applies only to parents and legal guardians driving their own children younger than 4 years old.

The statute, which grants certain exemptions, requires children to be properly harnessed in seats approved by the state police. Violations for not securing a child or for using an unapproved seat carry maximum $25 fines.

Nine Virginians were cited in January for violating the new statute, according to state police, who have not yet compiled statistics for February. Law enforcement officials predicted that the number of citations will remain low because the law applies only to infants who weigh 40 pounds or less.

"The number of citations has been insignificant--probably no more than 20 this year," said state police records officer Lt. E.E. Schneider.

Of the three infants who have died in Virginia traffic accidents this year, officials said, two were not secured in safety seats.

In the case of the third, highway officials said, a safety seat failed to save the life of its occupant because the car in which she was riding was virtually destroyed when it collided with a school bus near Lynchburg.

"These accidents are not good indications" that Virginians have taken the spirit--if not the letter--of the law to heart, said McAllister. Safety experts said they were baffled by the unusually high infant death rate when thousands of parents are taking advantage of safety-seat loan and rental programs.

"As fast as our auxiliary has been buying the seats, they've been going out of here," said Debbie Vogel, a spokeswoman for Arlington Hospital, which has rented 110 safety seats in the past two months. Alexandria Hospital has lent 75 seats to parents since July.

Statewide, more than 6,000 people have applied for free seats under the law's poverty provisions, which enable the poor to borrow infant seats, according to Ruth Robertson, a spokeswoman for the Transportation Safety Department. So far, 2,858 loan applications have been approved.

"The public awareness is still incredibly high," said Robertson, whose office received 9,000 inquiries about the new law in the first six weeks of the year.

Robertson said Joseph Palombo's mother was cited for not having her son in the safety seat at the time of last month's accident. The judge in the case later waived the fine, she added.