For the past four years, Corlis D. Jones has zipped in and out of Washington with just enough bodies in her car to meet the HOV regulations on Northern Virginia highways.

But this week, state troopers patrolling I-66 broke up the car pool when they discovered that the third person, stuffed into the back seat of Jones' Pontiac, was just that -- stuffed.

Trooper J.H. Hampton said he was patrolling I-66 eastbound Thursday morning when he pulled over Jones' 1978 maroon Pontiac with two people in the front seat, thinking that the car had violated the three-person requirement for commuters on I-66. As he got closer, he noticed what appeared to be a third face behind the others. He realized the frozen face of the third passenger "appeared to be a pillow packed with something."

Hampton and Sgt. Michael Clem, also patrolling the checkpoint one-half mile west of Rte. 7 (Leesburg Pike) could not remember what the dummy wore. "From the back, it looked pretty real," Clem said.

Not quite real enough, though, to keep Jones from getting a $35 ticket -- one of 23 the troopers issued that morning for HOV violations.

Jones said the dummy -- dubbed "Dolores" after actress Dolores Del Rio -- has been riding undiscovered for nearly six years, even before Jones joined the car pool.

"She belongs to the car pool, just like the monthly parking stickers belong to everybody," Jones explained.

Dolores, a Bozo-style children's punching bag, "goes way back," said another member of the car pool, who asked that her name not be used.

Dolores' mask is generally convincing, Jones said. "It's a punching bag. You put a stocking over its head to give it a normal face color, and a wig. From the back, it looks fine."

The carpool members now consider Dolores part of the family. When one member of the carpool moved to Atlanta, Dolores sent a goodbye card, one of the group said.

Jones, 28, of 3358 Woodburn Rd. in Annandale, and her female companion in the car were rather embarrassed when they were stopped by Hampton and Clem, the troopers recalled. "They kind of giggled, got red-faced," Hampton said.

Police said that adding inanimate "passengers" to meet the HOV-3 car pool regulations, enforced on I-66 between 7 and 9 in the morning and 4 and 6 in the evening, is not a new trick. "It's been done ever since I-395 bus lanes were created," Clem said.

Hampton said state troopers have stopped a few other motorists with dummy passengers, but have no idea how often fabric faces may zip by without detection.

"When somebody's driving down the road, it's hard to tell whether they're real or fake . You only look at them for a couple of seconds," he said.

Jones said that although the prospect of a $35 fine and three points off her driver's license upset her, "You can't fight it. It is wrong. Dolores will not be used again."

But she couldn't help pointing out that the black-and-white HOV signs do leave room for different interpretations.

"They never said it had to be three live bodies," she said.