It was a packed Arlington courtroom with unprecedented drama: The Honorable William H. Rehnquist was presiding.

The chief justice of the United States made a rare court appearance last week at the Arlington courthouse to celebrate the 100th birthday of the nation's juvenile court system.

He was also there to help the court's juvenile judges present driver's licenses to about 95 new teenage drivers. As Rehnquist settled into his seat at the bench, joining Judges George D. Varoutsos and Esther L. Wiggins, he seemed right at home.

"He's just another guy," Spencer Smith, 16, a student at Yorktown High School, said of the chief justice. "And he gave me my license--that was pretty far out."

Requiring new drivers to pick up their licenses during a ceremony at the courthouse is a uniquely Virginia tradition, Varoutsos, the chief judge of the Arlington County Juvenile and Domestic Relations District Court, explained to the expectant teenagers and their parents in Courtroom 11-A.

"Although, normally you don't get a ceremony such as this," he added, alluding to his special guest. "It's not only a special year, but a special day in Arlington."

Wiggins gave the teenagers a history lesson about the nation's juvenile court system, explaining that the first juvenile court was established in Cook County, Ill., 100 years ago.

Then Rehnquist, who was wearing his black robe with gold stripes, told the crowd that he's an Arlington resident, too, and therefore has "an interest in seeing qualified drivers on the streets."

Getting behind the wheel of a car is "a great responsibility," Rehnquist told the new drivers. Not obeying traffic laws can lead to tragic consequences, he said, recalling the driving duel on the George Washington Memorial Parkway three years ago in which three people were killed and one driver was sent to prison for 10 years.

In closing, Rehnquist said: "For heaven's sake, drive safely."

The crowd's verdict: a rousing round of applause.

CAPTION: Chief Justice William H. Rehnquist told the courtroom that driving is "a great responsibility."