The American Automobile Association warned yesterday that the number of drivers violating speed limits in the Washington area has increased in the past year while police have issued fewer speeding tickets.

"That's a collision course," said AAA spokesman Tom Crosby. "We'd like to see that trend reversed."

The association called for stepped-up enforcement of traffic laws by local police and urged motorists to reduce speeds. "Don't mar this holiday weekend," Crosby said at a news conference shortly before the start of the heavily traveled Thanksgiving period.

Average speeds increased 4 percent in the past year to 59.1 miles per hour on Maryland highways where a 55-mph speed limit is in effect, the AAA said, citing federal data. On Virginia highways, average speeds rose one percent to 52.9 mph. No similar data is available in the District, officials said.

At the same time, the number of speeding tickets issued by county, city and state police dropped by 4 percent in the Washington area in the past year, an AAA survey showed. The group cited decreases in speeding tickets in most counties and cities, but said tickets increased in Arlington and Prince George's counties.

Crosby said the trends reflected widespread "traffic lawlessness" and attributed the rise in speeding partly to lax enforcement. "They're getting away with it," he said.

Speeding appears to have increased throughout the United States in the last two years, according to federal officials, who said the reason for the rise is unclear. In Maryland and Virginia, average speeds on highways with 55-mph limits decreased from 1982 to 1983 before turning upward this year.

The AAA also pointed to data indicating increases in traffic accidents in the District, Maryland and Virginia in the past two years. In addition, the group said the amount of traffic on the area's highways appears to have risen.

Several local police agencies recently launched crackdowns on traffic violations. A four-week effort by Virginia State Police on the Capital Beltway resulted in 1,592 tickets, including 626 for speeding, along with what was termed a "significant decrease in the accident rate."

Lt. Herbert Northern, head of the Northern Virginia police division, said that 34 accidents occurred on Virginia sections of the Beltway during the crackdown from Oct. 22 to Nov. 16. In the previous 10 months, Beltway accidents averaged 54 a month, he said.

Maryland State Police began a campaign against speeding on major highways last summer. The move was triggered by concern over possible cutbacks in federal funds. Under current law, a state may lose up to 10 percent of federal highway aid if more than 50 percent of drivers exceed 55 mph.

Arlington County police also began an effort to reduce speeding in residential areas more than a year ago. The AAA survey linked the crackdown to a 30 percent increase in speeding tickets in the county in the last year.

Decreases in traffic tickets in other areas were attributed largely to shortages of police officers, including vacancies in Maryland and Virginia state police. Officials said the Northern Virginia division has been unable to fill 19 positions for state troopers because of insufficient funds. In addition, some departments have shifted police from traffic to criminal investigation and other duties, officials said.

In Montgomery County, a 13 percent decrease in speeding tickets was attributed to the elimination of a "productivity system," under which the number of tickets issued was included as a measure of an officer's productivity.