The chief judges of the District's federal and local courts joined a group of District lawyers yesterday to draw attention to a growing problem: despite an explosion in drug prosecutions and a need for more citizens to serve on juries, many people don't understand the importance of serving and don't show up.

D.C. Superior Court Judge Fred B. Ugast and Chief U.S. District Judge Aubrey E. Robinson Jr. held a rare joint news conference to announce a continuing education project about one of the two civic responsibilities embodied in the U.S. Constitution. The other is voting.

Standing just outside the D.C. Superior Courthouse, because no cameras are allowed inside, the two judges made their appeal in coordiation with the private Council for Court Excellence, a local group that encourages court efficiency.

During the fiscal year that ends tomorrow, 80,000 people have been on jury duty in the federal and local courts in the District. That's one-fifth of all the people on the juror rolls, which are compiled from lists of registered voters and residents with D.C. driver's licenses.

In 1989, 41 percent of the D.C. residents summoned for duty for federal and Superior Court panels actually reported. The national average is between 40 and 50 percent.

Both courts have reduced the time required on jury duty. The federal court has cut its period from 30 days to two weeks.

"Unfortunately," Robinson said, "we find that a large number of potential jurors fail to respond to either {qualifications} questionnaires {or jury} summons."

With only limited resources to follow up on those who don't respond, the courts are depending increasingly on the good will of the city's conscientious citizens, Robinson said.

"Jurors bring many different perspectives to the courtroom, and therefore it is very important that all citizens of our city make an effort to serve when called so that every case receives consideration by persons from all parts of the community," Ugast said.

According to preliminary results of a survey of jurors here by the Arlington-based National Center for State Courts, more than half of the people serving on juries here said they were "eager to serve again." Three-quarters of the jurors have a "favorable attitude" about their jury experience, and 58 percent said their attitude was more favorable after jury service than before.

During the last year, D.C. Superior Court has made several refinements in the one day, one trial system, under which a person is called for duty for only a single day and must serve that day, or if picked for a trial on that day, for the duration of the trial.

In fiscal 1989, 61,000 jurors were used in Superior Court for 1,174 criminal trials and 5,350 civil trials. No statistics were available for the year that ends tomorrow.

The one day, one trial system permits few excuses for avoiding jury duty, and nowadays people who once would have gotten off juries -- doctors, lawyers and reporters, for example -- usually have to serve. Residents who can't serve on the day they are summoned may arrange for a deferred date. Superior Court also has a child-care center for children 2 to 14 while a parent is on jury duty.

The number of jurors needed in federal court here doubled over the last year, from 8,097 in fiscal 1989 to 16,000 in 1990. While the number of trials rose from 176 to 228, James Davey, clerk of the U.S. District Court, said the biggest part of the increase came because of the large number needed by high-profile cases such as those from the Edmond drug gang and Mayor Marion Barry.