A mother driving from Alabama to Loudoun County forced two of her daughters, ages 8 and 10, to take turns riding in the trunk because the four-door sedan was cramped with three other passengers and a dog, authorities said yesterday.

Cheryl Ann Schoonmaker, 38, has been charged with abuse and cruelty to children for allegedly rotating the two girls in and out of the trunk of the Nissan Sentra during the July 1 trip, which took more than eight hours.

Schoonmaker was driving from Alabama, where she has relatives, to the Loudoun home of her ex-husband, the girls' father, said Kraig Troxell, spokesman for the Loudoun sheriff's office. Also riding in the car were the former couple's 12-year-old daughter, a 12-year-old family friend and an infant in a car seat.

"It's amazing to me what some people will consider doing to their children," Loudoun Commonwealth's Attorney James E. Plowman said yesterday. "I don't understand -- they're children, not pets. Not that you would put your pet in the trunk. They're not cargo, I should say."

The incident was at least the third time in less than two months that local women have faced criminal charges after allegedly putting their children in car trunks. In June, a Frederick woman was charged with reckless endangerment after a police officer watched her help her 9-year-old son, her 3-year-old daughter and an 8-year-old friend into the trunk in a shopping mall parking lot. When the police officer pulled her over, the woman said the children had wanted to ride there.

Earlier this month, Tamatha Parker, 33, of Quantico was charged with child abuse after Fredericksburg authorities accused her of locking her two 5-year-old children in the car trunk as punishment for misbehaving in a store.

In the most recent case, Curtis Schoonmaker, the father of the three girls, said he was shocked when his daughters came to him the day after the July 1 trip and blurted out the conditions of their ride. He said that the children appeared unharmed but that the trip to Aldie "made them uncomfortable enough that they came to me and told me."

Schoonmaker said that he has custody of the three girls and that they had been visiting their mother for a five-day vacation. This was the first time they had ever told him about being put in the car trunk. However, he said that at other times, they told him about riding in overcrowded cars with their mother.

He said the girls told him that the 12-year-old family friend was allowed to ride in the car, as was the dog, a Boston terrier. "I don't think my feelings need an explanatory comment about that," he said.

He said that according to the daughters, the mother could have rented a larger car but chose the Nissan Sentra because it was cheaper. "She thought there was no problem with this," he said.

Cheryl Ann Schoonmaker apparently made some effort to ensure that the child riding in the trunk had air and light, Troxell said. He said the car had a back seat designed to fold down, allowing space for large packages in the trunk to extend into the passenger compartment. According to Troxell, Schoonmaker drove with the seat folded over so that there was an opening from the back seat into the trunk. Another child rode seated on the back of the collapsed seat.

Schoonmaker was arrested Friday and was charged with two felonies. Each charge is punishable by up to five years in prison. It could not be determined whether the other occupants of the car were wearing seat belts.

Plowman said the charges were appropriate, even though the children came through the incident unscathed.

"You're causing this child to be in danger. They're unrestrained in a hot, enclosed, dark environment with probably poor oxygen. If that car is in an accident, it would be extremely dangerous," he said.

Schoonmaker, who was released by a Stafford magistrate on $5,000 bond, could not be reached at her home. She will be arraigned in Loudoun Juvenile and Domestic Relations Court on Friday.