Slugs are commuters trying to get from Point A to Point B with as little fuss and cost as possible. They seek drivers who also want to get to their destinations quickly, but prefer a little more control during the ride.

The symbiotic relationship between the two arose from the need to overcome a common obstacle -- government-imposed, travel-lane restrictions designed to ease congestion during peak commuting hours.

In the Washington, D.C., metropolitan area, the two groups have come together to beat the system and have evolved over the last three decades to become one of the nation's most efficient mass-transit systems.

Here's how it works.

The high occupancy vehicle, or HOV, lanes require at least three riders per car.

Since traffic in the HOV lanes generally moves faster than traffic in the regular lanes, commuters prefer to use the HOV lanes.

Hence the need for cooperation.

So one set of commuters, the slugs, wait in lines at the commuter lots while the drivers ride by and shout destinations through their open car windows.

If the destinations match, the required number of slugs jump in the strangers' cars and off they go to destinations such as "14th and K," "The Pentagon," "Rosslyn," "Springfield" or "Crystal City."

Dave LeBlanc, author of the book "Slugging: The Commuting Alternative to Washington, D.C.," said slugging first began to occur after HOV lanes opened in 1971.

"It really is the common citizen's solution to a problem. They had to figure a low-cost way of doing business," said LeBlanc, a U.S. Army lieutenant colonel. "It's probably the most cost-effective means of transportation in the country."

LeBlanc said he has heard rumors of fledgling slug systems in the Dallas-Ft. Worth and San Francisco areas.

"It kind of sounds like the infancy of our slugging system when it started in the '70s," LeBlanc said.

According to LeBlanc, the term "slug" came from the origins of the custom.

Evidently, a bright driver of yesteryear needed warm bodies to qualify for the HOV lanes and drove to local bus stops looking for riders, LeBlanc said.

The idea caught on, and soon riders waiting at bus stops started declining bus rides in favor of the free car rides.

The bus drivers began to call reticent riders "counterfeit commuters," LeBlanc said.

The renegades, who were jumping into cars with strangers, began calling themselves "slugs," after false coins.

Little is known of the custom outside of our area.

People who slug say that their friends and family, who are unfamiliar with the idea, cringe at the thought of riding to work with unknown people.

LeBlanc understands how the idea might seem dangerous to those who have not been exposed to the practice.

"It just sounds hare-brained. It really does," LeBlanc said.

But LeBlanc said people should think of it as "instant car-pooling."

"The only difference between car-pooling and slugging is how well you know the occupants of the car," LeBlanc said.

Prince William County Board of Supervisors Chairman Sean Connaughton, R-at large, said the county encourages mass transportation to ease traffic congestion and improve air quality.

The county also recognizes that slugging is an integral part of the community, he said, and "We do everything we can to stay out of the way.

"Only in Prince William County is it a good thing to be called a slug. The system works," Connaughton said.

LeBlanc is also the Web master of www.slug-lines.com, where slugs and drivers can find the latest information about new slug lines, existing slug line locations and slug stories.

Slugs and drivers can also use the Web site to submit horror stories to police those who are not behaving properly or to tell how they met someone they graduated from high school with in 1976.

Some stories warn people to avoid the brown Camry because of the mess inside or to beware of the crazy driver someone dubbed the "Blue Van Terror."

Another story tells of the man who forgot that he drove to work one day and slugged home, only to realize his mistake as his driver pulled into the Tacketts Mill parking lot.

The writer of the story said the man slapped himself on the forehead with the heel of his hand, got out of the car and called his wife to beg for a ride home.

Staff writer Keith Walker can be reached at (703) 878-8063.