Two Fairfax County residents were killed and two others were injured during the weekend in separate car accidents that police attributed to alcohol.

Brenda Nichels, 26, of 8392 Oxbridge Ct., Springfield, was killed about 11 p.m. Friday after the car she was driving on Danbury Forest Drive was struck by a vehicle that crossed into her lane.

Police said the driver, Robert Johnson, 28, of 5676 Kirkham Ct., Fairfax, fell asleep at the wheel. Leslie Bryan, a passenger in Nichels' car, was treated for minor injuries at Fairfax Hospital and released, police said.

Johnson was charged with driving while intoxicated and released pending a court date.

County police also charged a 17-year-old McLean youth with driving while intoxicated after the car he was driving crashed in a Tysons Corner parking lot, killing one passenger and injuring another.

Police said the youth, who they did not identify, was speeding about 2 a.m. when he lost control of the car. Richard C. Manlove, 17, of McLean, was dead at the scene, police said. The other passenger, Scott Fenlund, 18, of Falls Church, was treated at Fairfax Hospital and released.

The driver was released in the custody of his parents.