A three-month experiment with citizens band radios by Virginia State Police has been so successful the state is planning to buy as many as 1,000 CB units for an expanded experiment and is launching a statewide campaign to enlist voluntary help from CB radio owners in reporting accidents, drunken driving and excessive speeding.

State police were given 14 CB radios by the Virginia Highway Safety Commission last fall to aid in a crackdown on speeding and to help combat the state's near-record number of highway fatalities.

The CB radios not only have helped police locate accidents and other emergencies along the state's 62,000 miles of highways, but have brought a "surprising number of reports of excessive speeding and drunk and reckless driving," said John T. Hanna, safety commission director. "Truckers were especially helpful in using channel 9 - the emergency frequency - to report drunken driving . . . they don't like the drunks."

The use of CB radios to assist police appears to be a new twist, since truckers and motorists frequently have been using the radios to alert each other to speed are concerned about speeding, particularly excessive, reckless speeding, and "we have the strong support of Virginia's licensed CB operators for this program."

He said the $40,000 program to distribute the additional CB radios is being submitted to the National Highway Traffic Safety Administration since federal funds are involved. The radios would be given to local, county and state police in three counties, not yet chosen, to test the effectiveness of their use in police work. If the three-county experiment is successful, CB radios would be given to police and sheriff's offices all over the state. Several other states, such as Georgia, already are testing use of CB radios by police, Hanna said.

An extensive network of CB radios is necessary, said Hanna, because their range normally is only one to 10 miles.

"We hope this program will improve emergency communication in the state," said Hanna. "And the heart of it is the voluntary help we expert will come from motorists and truckers in both bringing quick assistance in accidents and in helping prevent them."

The 1,139 persons who died in Virginia motor vehicle accidents last year, most killed during the summer and fall, represented the second highest highway death toll in the state's history, according to state police statistics released last week.

Drunken driving, Speeding, failure to use seatbelts and a 6.5 per cent increase in traffic on Virginia roads contributed to the high death toll, said Hanna. Until last May, the number of Virginia highway fatalities, as well as other accidents, had declined steadily for four years.

Most of the fatalities occurred on secondary roads, particularly in the eastern part of the state, and involved local residents, Hann said. Many also involved pick-up trucks or small cars and women drivers, said Hanna, reflecting their increased numbers on the highways.

Drunken driving, speeding and the declining use of seatbelts is causing state officials particular concern. Alcohol is involved in 60 per cent of the state's fatal accidents, compared with a national average of 50 per cent. "And seatbelt usage is down to almost nothing," Hanna said. "In 1974 and 1975, about 28 per cent of the drivers were using seatbelts and now it's down to only 13 or 14 per cent."

State police began cracking down on speeders in September as the death toll began to mount, and a special $180,000 grant from the state safety commission enabled police to put 500 troopers on overtime weekend duty last month, resulting in a 30 per cent increase in speeding tickets.

Before the crackdown, police had issued 20,000 fewer tickets in 1977 than they had in the first eight months of 1976, according to police records, despite the state's reputation for strict enforcement of speed limits.

Virginia's reputation led Transportation Secretary Brock Adams to cite the state recently as the state which had achieved the best compliance with the national speed limit of 55 miles an hour.

While many police forces have an unwritten policy of permitting a 10-mile-an-hour margin of error - thus generally not stopping motorists unless they are more than 10 miles an hour over a speed limit - Virginia State Police have no such policy. A spokeman for the state police said last week that individual state troopers may allow a 5 mile-an-hour margn of error, but even that is unwritten and depends upon the judgment of the individual officer.

"One reason there probably are few arrests under 5 miles an hour is that judges throw out the cases and the officers just don't waste their time on them," the spokesman said.