Three men, two of them brothers, died early yesterday in two single-car accidents in Arlington. Police said alcohol was a factor in one accident, and one motorist was charged with driving under the influence of alcohol.

The brothers were killed and a third man was seriously injured in the first accident, shortly after midnight, when the car in which they were riding ran off eastbound Rte. 50 and landed in a ravine just east of Court House Road, police said.

Julio Hernandez, 31, of 1825 New Hampshire Ave. NW, and his brother, Jose Hernandez, 23, of 1221 Massachusetts Ave. NW, were pronounced dead on arrival at Arlington Hospital.

Salvador Alfaro, 28, of 4119 N. Four Mile Run Dr., Arlington, was reported in stable condition at the same hospital with head and internal injuries.

Arlington police spokesman Tom Bell said the vehicle's driver, Luis Alfredo Casula, 27, of 1425 T St. NW, was charged with driving under the influence and driving with a suspended driver's license. Casula was being held in lieu of $10,000 bond.

The car's occupants apparently were not wearing seat belts, police said.

In the second accident, shortly after 2 a.m., a car ran off a southbound lane of the George Washington Memorial Parkway near the 14th Street Bridge, hit a guardrail and broke in two, police said.

Alan A. Fonseca, 20, of 6425 Fenstra Ct., Burke, who was a front-seat passenger, was killed. Critically injured were the car's driver, Michael A. Beach, 19, of Alexandria, who was taken to Washington Hospital Center, and Colleen Petty, 19, also of Alexandria, who was taken to Arlington Hospital.

A third passenger, Steven Schneider, 19, of Alexandria, was treated at Arlington Hospital.