Five years after Virginia switched from twice-a-year to annual automobile safety inspections, police report that fewer inspections did not lead to more auto accidents as some critics had feared.

Last year, 2.8 percent of all traffic crashes were attributed to defects in inspectable parts, such as failed brakes or broken headlights, said Capt. R.L. Bumgardner, a safety officer with the Virginia State Police.

In 1981, the last year semiannual inspections were conducted, 3.6 percent of traffic accidents were caused by defective inspectable items, he said.

The decline has less to do with the frequency of inspections than it does with improvements in inspector training, Bumgardner said.

"In January 1985, we implemented a program that requires that inspector/mechanics be licensed and that the license be renewed every three years," he said.

"We have also intensified the training of the state troopers who supervise the inspection stations."

The new program is responsible for inspectors finding more defective items, Bumgardner said. The percent of state-inspected vehicles found to have defective parts jumped from 20.75 in 1981 to 33.75 last year, he said.

But some critics say inspectors are finding more defective parts because of the longer time between inspections.

"We've noticed that the defects are compounded by the length of time," said Vance Wortman, owner of Briar Oaks Exxon Station, an authorized inspection station in Fairfax County. "The extent of the damage is more serious and might have been corrected if caught earlier."

In Maryland, safety inspections are done at the time the car is purchased. Though emission inspections are required yearly, no further safety inspection is required as long as the ownership does not change.

In the District, automobile inspections are required annually.

"I am very pleased that the statistics show that annual inspections have not in any way affected the safety of the traveling public," said Sen. William T. Parker (D-Chesapeake), a sponsor of the 1982 Virginia legislation that eliminated the twice-a-year inspections.

"I'm kind of amazed," Sen. Madison E. Marye (D-Montgomery) said of the police statistics. Marye opposed the 1982 legislation.

"I'm not questioning how state police arrived at the figure," he said, "but it seems that there are other factors involved. Maybe people are driving newer cars."

Marye said that annual inspections are probably sufficient for new cars but that more frequent inspections should be required for older cars.

"I think inspections are vital," said James Shiflett, while waiting in line this week to have his 1986 Dodge Daytona inspected. "But I was glad to see it go to once a year. It's hard enough getting here once a year and even harder twice a year."

Wortman said that many people put off having their cars inspected until the last minute. Several motorists in line this week at Wortman's station said they were supposed to have cars inspected by the end of June but did not make time or were scared away by long lines.

"Everybody procrastinates," said David Nash, a college freshman in line for his first inspection. "I went to another station {Tuesday} afternoon. I saw 13 cars lined up ahead of me . . . . That's why I'm here today."