An early-morning joy ride by 12 Virginia teen-agers ended with one of them dead and four seriously injured yesterday when their pickup truck overturned near the Woodrow Wilson Bridge and spilled them onto the Capital Beltway.

Seven others, aged 17 and 18, escaped serious injury in the accident which area police called the worst involving teen-agers since 10 youths were killed in April 1979 when a pickup truck slammed into a tree in Anne Arundel County.

The latest accident occurred at 12:45 a.m. after, one of the riders said, the youths had exhausted their supplies of beer and headed for the Maryland suburbs where beer purchases can be made until 2 a.m. In Virginia beer sales end at midnight.

Virginia State Police said it was amazing that more of the youths in the latest accident wre not more seriously hurt. "They were all just tossed everywhere -- right onto the fast lane [and] into incoming traffic," said trooper Robert Giambrone.

He credited the drivers of two tractor-trailers with maneuvering to avoid the youngsters. "The drivers would have run over eight of them if they [the drivers] hadn't reacted quickly."

Steven R. Walter, 19, a Detroit native who had been living at the Alexandria home of his 17-year-old fiance, was killed instantly when he was flung from the truck bed onto a concrete median barrier, rescue workers said.

"It was very confusing scene," said trooper Giambrone. The truck was headed onto a ramp from U.S. Rte. 1 in Alexandria to the Maryland-bound lanes of the Beltway when the driver lost control, he said.

Giambrone said that the driver, Calvin Canup, 18, of 7927 Frye Rd., Fairfax County, twice tried to regain control of the vehicle. But it jumped over the Beltway's median barrier and came to rest on its roof in the west-bound lanes.

The youths had been out since about 6 p.m. "four wheeling" -- a kind of exhilarating high-speed hayride -- on the back roads of hills of Fairfax's Springfielld section, according to one of the injured.

"It was past midnight and we had run out of beer," said 18-year-old Steve Drevenak of East Groveton Street in Fairfax. "We were on our way to buy some more in Maryland since you can't buy beer past midnight in Virginia.

"I was in the cab and half asleep. Suddenly I felt the truck sliding, I don't remember anything else except waking up in an ambulance."

"There were four people in the cab and eight people in the bed of the truck at the time," Giamborne said. "The cab was just squished."

"It's a tragedy, real tragedy," Mrs. Stephen Friedheim mother of the dead man's fiance, kept repeating, in an interview yesterday. Walter had planned to marry her 17-year-old daughter Renee, as soon as he could enter a trade school and earn enough money to support her, the daughter said.

"I'm very lost," she said. "We were very much in love and had never gone out with anybody else."

State police said that charges have not been filed pending further investigation. Most of the injured were classmates from Fairfax's Mount Vernon High School.

Both driver Canup, and Traci Stachurski, 18, 8134 Pine Lake Ct., were admitted to Alexandria Hospital with skull fractures. Spokesmen there yesterday said their conditions were serious and critical, respectively.

Martin Manion, 17, 8502 Bound Brook La. and John Devouelos, 17, 8629 Mount Vernon Hwy. Fairfax were listed in good condition at Clinton Community Hospital with multiple fractures and lacerations.

State police said two victims left hospitals before they could be interviewed and postively identified. The remaining five victims were treated for injuries ranging from lacerations to bruises and then released. They were listed as Drevanak; David Jeffries, 17, of Alexandria; Mark Hammond, 17, 5105 Mount Vernon Hwy., Sheri Corallas, 17, of Alexandria, and Carla Knox, 18, 5408 Danville St., Springfield.