The 617-space parking lot at Bethesda's Grosvenor Metro Station used to be packed by 8 a.m., while a larger parking facility a mile north at the White Flint station was underused. Today, more than two weeks after Montgomery County and Metro officials began experimenting with changes in parking fees, things are nearly reversed.

There are parking spaces to spare at Grosvenor, while the lot across from the Metro Station a quarter of a mile north of the White Flint shopping mall is nearly filled by the end of rush hour.

The shift in parking customers began Sept. 3, after parking fees at Grosvenor were doubled to $2 and those at White Flint were waived.

The experiment in diverting traffic, one Metro official said, "seems to be a success."

"We're not trying to draw any conclusions at this point, but we are pleased so far," said Edward Daniel, Montgomery County's Metro liaison.

At Grosvenor, just north of the Capital Beltway, there are about 200 parking spaces still available at 9:30 a.m., at the end of the morning rush period, officials said. And the 930-space White Flint parking facility, where free parking is being offered through Nov. 17, is now about 90 percent filled by the close of rush hour, Daniel said.

Often by noon, officials said, the White Flint lot is filled. Before the $1 parking fee was temporarily waived, only about half the spaces were filled after rush hour.

The experiment "is similar to what the private sector does to influence demand," Daniel said.

The $2 charge will remain in effect through June 30, the end of Metro's current fiscal year.