The Prince William County Police Department is reminding county residents to buckle up when traveling in a motor vehicle. The warning follows four fatal accidents in slightly more than two weeks, spokeswoman Kim D. Chinn said.

Derrick Bresser, 17, of Dale City, was killed Sept. 29 near the intersection of Minnieville and Spriggs roads when the car in which he was a passenger hit a tree and he was ejected. Bresser was not wearing a seat belt. Two other people in the car, both of whom were buckled in, received only minor injuries, Chinn said.

A leading cause of fatalities is ejection on impact, which can be avoided if motorists are secured by safety belts, she said.

"It really brings home the point how much seat belts contribute to motorists' safety," Chinn said. "We drive up to accidents all the time, and, as police officers, we hate it because we know that things might have ended differently if they were wearing only a seat belt. Police say all the time, 'If only this guy had had his safety belt on.' "

So far this year, 26 people have died in accidents on Prince William County roads. There were a total of 31 traffic deaths last year. There have been 21 accidents involving fatalities -- some had multiple victims -- compared with 27 fatal accidents last year.

Fatal accidents occurred on Sept. 14 on Blackburn Road, on Sept. 15 on Morningside Drive and on Sept. 17 on Bacon Race Road. None of the victims wore safety belts, Chinn said.

Virginia law requires all front- seat occupants of motor vehicles to wear seat belts whenever they are traveling on highways. The law also requires children under 4 who weigh less than 40 pounds to be secured in a child safety seat approved by the U.S. Department of Transportation. If motorists cannot afford the child safety devices, the Department of Motor Vehicles has programs to assist parents in getting one, Chinn said.

Studies have shown that safety belts reduce serious injury. Even in accidents that involve excessive speed, people secured in safety belts have walked away without being badly hurt, Chinn said.

"We are concerned about the tragic loss of life and serious injuries that are occurring on the highways of Prince William County," Police Chief Charlie T. Deane said through Chinn. "I would encourage all citizens to use their safety belts . . . . Please buckle up."

Earlier this year, Prince William County police sponsored a billboard campaign to remind residents to buckle up. More than 100 signs were placed at strategic points around the county, and read, "Safety Belts Hold Lives Together."

Last year, police randomly rewarded motorists who were buckled up by giving them mugs with the slogan "Mugged by Chief Charlie T. Deane, Prince William County Police" in vivid blue letters.

An episode of the television series "Rescue 911" scheduled to be shown this season was filmed in Woodbridge and centered on seat belt safety, Chinn said. In the episode, Prince William County residents David L. Bell, 20, Ethan Funston, 17, Christopher T. Paxton, 18, and Steven D. Ingram, 18, were interviewed about a near-fatal accident they were involved in on April 27, 1989, on Hoadley Road. The youths, who have all recovered, contacted the show's producers to tell how the accident convinced them to buckle up when traveling in a motor vehicle.