More commuters appear to be leaving their cars at home and riding the bus to the Huntington Metro station, according to the initial results of a Fairfax County experiment designed to ease parking space shortages at stations on the Yellow and Orange lines.

However, the county's program seems to have had little effect on the parking situation at four Orange Line stations -- Vienna, Dunn Loring, East Falls Church and West Falls Church -- where the Metro parking lots continue to fill before the end of the morning rush hours despite the county's program.

Under the program, the county raised parking fees and lowered bus fares on routes serving the stations.

"It's too early to draw any definite conclusions" about the effectiveness of the one-year program, which began March 23, said Andrew Szakos, the county's chief of transit operations. "Huntington is very encouraging; the others are somewhat encouraging."

Since the program was begun, bus ridership on the selected routes has increased 30 percent overall, with the biggest changes on the buses serving Vienna and Huntington, where ridership rose 49 percent, according to the report released yesterday.

Metrorail ridership has increased 5 percent overall at the five stations during the morning peak period. But Huntington is the only one of the five stations where parking has clearly improved. Before the program, the Huntington lots' 2,282 spaces were filled by 8:30 a.m. Now the lots do not fill until midday.

Parking lots at the four Orange Line stations are full by 8:45 a.m., the county report said. Vienna's parking lots are full by 8:15 a.m., or 15 minutes earlier than before.