This story was corrected on Nov. 10, 2009. An explanation of the correction is at the end of the story.

The wheels are turning on finding places for large trucks to park.

The county's Department of Transportation has opened up more than 600 spaces for the vehicles to park, all of them in Germantown and Silver Spring, mostly by lifting block-by-block restrictions that county leaders had not realized were preventing the vehicles from parking.

Under a three-month-old county law trailers and "heavy commercial vehicles" (more than 10,000 pounds, 21 feet long or eight feet tall) can park on the street overnight only along roadways with industrial zoning on both sides. The penalty is a $75 ticket. Recreational vehicles are not allowed to park on public roads unless they are actively being loaded or unloaded.

After the law took effect July 1, leaders learned that much of the 14 miles of industrial roadway was lined with "No Parking" signs and other restrictions, said Councilman Michael J. Knapp — whose proposal was merged with County Executive Isiah Leggett's to arrive at the current law.

Responding to a request from Knapp, DOT surveyed the 14 miles and lifted many of the restrictions, adding 608 spaces in Germantown and Silver Spring.

The stretches of road with the most new spaces are along Seneca Meadows Parkway between Observation Drive and Germantown Road (246 spaces) in Germantown and along Prosperity Drive between Cherry Hill Road and Tech Road (125 spaces) in Silver Spring.

Also at Knapp's behest, DOT director Arthur Holmes agreed to allow large trucks to park in a small portion of a 200-space Park-and-Ride lot on Clopper Road in Germantown, until the end of next year.

Even though Knapp regularly sees the Clopper Road lot full of trucks, the recent solutions leave the longer-term issue unsettled, Knapp said, largely because officials do not know how many spaces are needed.

"It's tough to gauge any demand. There is some demand, but there's no way for me to quantify it," said Knapp (D-Dist. 2) of Germantown.

Some of that demand could be met in Gaithersburg.

The city's Planning Commission is expected to issue its recommendation today on a proposal that would allow 120 vehicles to park overnight in Metropolitan Grove.

On an adjacent 5-acre lot, George F. Stevenson Jr. and his family want to allow other family members to park as many as 20 dump trucks.

The council is set to take the issue up on Nov. 16. Public comment is being accepted until 5 p.m. Friday.

Where to park?

In recent weeks, county officials have opened up more than 600 parking spaces along county roads for large trucks.

Germantown, 398 new spaces:

38 spaces on Amaranth Drive, from Middlebrook Road to the end

114 spaces added on Century Boulevard, between Aircraft Drive and Father Hurley Boulevard

246 spaces on Seneca Meadows Parkway, between Observation Drive and Germantown Road

Silver Spring, 210 new spaces:

48 spaces on Old Columbia Pike, between Tech Road and Industrial Parkway

125 spaces added on Prosperity Drive, between Cherry Hill Road and Tech Road

26 spaces added on Prosperity Terrace, from Prosperity Drive to the end

11 spaces added on Whitehorn Court, from Prosperity Drive to the road's end

Correction: A previous version of this story omitted that under the county's new truck parking law, recreational vehicles are not allowed to park on public roads unless they are actively being loaded or unloaded.