Five area residents were fatally injured in unrelated traffic accidents here over the weekend, including one that involved a Prince George's County police officer, authorities reported.

In the latter incident, a man identified as Joseph M. Moore, 19, of 11700 Brandywine Rd., Clinton, was attempting to cross Rte. 301 on foot just north of Brandywine Road at 4:47 a.m. yesterday when he was hit by a county police cruiser traveling south.

Police officials said the officer driving, Carl G. Lavsa of the Clinton station, was slowing to make a right turn when Moore stepped off the median strip and into the path of the police car. "The officer did not see the pedestrian until impact," a police spokesman said.

Moore was taken to Southern Maryland Hospital, where he was pronounced dead at 5:39 a.m. No charges have been lodged against the officer, officials said.

On Saturday afternoon, 33-year-old Jasumati Mastry of 7038 Nashville Rd., Lanham, was fatally injured in a two-car collision at Good Luck Road and 96th Avenue in Lanham, Prince George's police said. They said she was a passenger in a car being driven west on Good Luck Road by her husband when it collided with a northbound car on 96th Avenue.

The woman was pronounced dead at the Washington Hospital Center about an hour after the 5 p.m. accident. The other motorist, identified as Talaya Jordan, 26, of 9102 Springhill La., Greenbelt, was admitted to Doctors' Hospital of Prince George's County, where she was listed in fair condition last night. Police said Jordan was charged with failure to yield the right of way.

A third victim, Forest Luckett, 61, of 10915 Warwick Ave., Fairfax City, died at Fairfax Hospital yesterday of injuries suffered Saturday when his car was struck in the side by another automobile at Little River Turnpike and Hummer Road near Annandale, county police said.

They said Luckett was driving east on the turnpike about 8 p.m. and was attempting to turn left onto Hummer Road when his car was struck in the passenger side by a westbound automobile.

In earlier incidents, Timothy M. Jones, 23, of 1119 Copley Ave., Waldorf, was fatally injured about 2:30 a.m. Saturday when he was struck from behind by a vehicle driving on the wrong side of the road as he was walking in the northbound lane of Old Washington Road in Waldorf, and Bruce P. Davidson, 29, of 2110 Forest Glen Rd., Silver Spring, was killed about two hours later when the motorcycle he was riding crashed into a guardrail on the Capital Beltway near Rockville Pike.