Beyond the split rail fence off busy Columbia Road, the hum of traffic gives way to the cool green quiet of the woods.

A vast yellow poplar, two centuries old and with a gnarled trunk 20 feet around, guards the pathway. A fiery blue dragonfly lights upon a leaf. A barred owl sweeps overhead on great soundless wings. The Little Patuxent River flows by.

"This is my sanctuary," said middle school teacher Audrey Bross. She finds peace and calm here and comes up with some of her best lesson plans during her daily four-mile jog along the section of Columbia's 93-mile pathway system that runs along the outskirts of her Dorsey's Search neighborhood.

On some summer days, such as this one, she enjoys an encounter with a deer. On winter afternoons, when she runs after school, sometimes there are rabbit tracks in the snow.

"I don't care how tired I am. I come home, change my clothes," Bross said.

The trail awaits.

"It's meditation."

From the time Columbia began taking shape four decades ago, the extensive pathway system was seen as an integral part of this planned community, a conduit for transportation, recreation and neighborliness.

Without fanfare, the system was completed in June with the paving of a final segment of path off Indian Summer Drive in Columbia's newest village, River Hill.

"We finished our last pathway," said Denis Ellis, assistant director of open space management for the Columbia Association, which publishes a large foldout map of the system. "Our Columbia system is completed."

Maybe the quiet ending to the project was appropriate, because the quiet of nature is what many users seem to treasure the most about the pathway system.

"This is the one treat during the day," said Evelina Anderson, matching strides with two co-workers during their lunch-hour walk on the path around Lake Elkhorn in the village of Owen Brown. Glimpses of a fat groundhog or a mother duck caring for her brood of ducklings are refreshing breaks from their workday routines.

"There goes the heron," Pam Jeffries said as the prehistoric-looking long-neck bird rose from the lake. "You wouldn't believe how easily they catch fish."

In the offices of US Foodservice Inc., the giant food distribution company where the three colleagues work, snacking is almost unavoidable. The friends said their daily walk keeps them in shape.

"When I started [the job] people said I'd gain 20 pounds, " Jeffries said with a wry smile. She has defied those predictions.

The pathways running throughout Columbia's 10 villages, which are maintained by the Columbia Association, interconnect with about 30 more mostly paved miles of trails, including a well-used pathway around Centennial Lake maintained by Howard County.

The two-mile path around Lake Elkhorn joins with the county's Patuxent Branch Trail, which runs more than 3.5 miles south over a historic railroad bridge, through the remains of the old Guilford quarry and mill sites, then along the Little Patuxent River down to the town of Savage.

Cyclist John Fiveash of Glen Burnie, who is getting in shape for a 180-mile ride from Georgetown to Cumberland, is a regular on that segment of path.

"The real beauty of these trails" is they provide the pleasure of riding "without being in traffic," he said.

That observation would have pleased Columbia's founder, the late Jim Rouse. In a speech at a 1967 conference on urban transportation organized by the U.S. Department of Housing and Urban Development, Rouse hailed Columbia's pedestrian walkways as key to the transportation in the innovative new community, allowing residents to move from place to place "free of any conflict with automobiles or public transportation traffic."

At the same time, newspaper advertisements were using the pathway system to help sell Columbia as the "next America" -- rising on former farm fields between Washington and Baltimore.

"Many of our country's cities have gone far down the road to being unlivable," one ad said. "Columbia has taken a different path. Come walk it."

Rouse wasn't the first to recognize the appeal of a peaceful car-free pathway within a modern community. He was drawing heavily upon the innovations of planners, including Clarence Stein and Henry Wright, who brought the Garden City Movement to the United States from England much earlier in the last century.

"They designed Radburn, N.J., in 1929 around the theme of mitigating the conflicts that would emerge between pedestrians and automobiles," said Kelly J. Clifton, a specialist in pedestrian planning issues at the University of Maryland's National Center for Smart Growth Research and Education.

Greenbelt was designed along similar principles in 1935 and maintains its hallmark pathway system. Reston, a planned community in Virginia, started in 1963, just a year before Columbia. It boasts 55 miles of trails.

In Columbia, the interface between cars and people endures as a planning challenge.

As traffic endures, so does the need for the trails, officials say, as an anchor for Columbia's 3,400-acre open space system, a route for children to walk to neighborhood schools and as a path for some adults to walk to work, though not a significant number do so.

"According to the 2000 Census, only 1.3 percent of workers in Columbia walked to work, which is below the Maryland state average of 2.5 percent," Clifton said.

Because many workers leave Columbia for jobs in Washington and Baltimore, that number isn't surprising, she said.

There are some concerns about safety and security in the pathways, Clifton said. She said many studies have examined residents' concerns about crime and trail use before and after construction.

"Fears of crime, particularly fears that strangers and trespassers would be able to enter property from the trail, and the loss of privacy and quiet are common. However, luckily, these fears are often not realized," she said.

For Columbia residents, the trails have always been a part of life. Worries were raised in 1999 after two men were fatally shot near the pathway through the village of Oakland Mills. The slayings remain unsolved.

Since then, fears have eased. Residents have staged cleanups and other community activities focused on the pathway, village manager Sandy Cedarbaum said.

"The paths are well-maintained," she said. "People should be able to enjoy them."

Howard County police and county park rangers regularly patrol the paths on foot and by bicycle. Numbered global positioning markers were recently installed at each of the 170 playgrounds along the pathways to help emergency workers respond to calls.

"The bike paths are just as safe as any other area of Columbia," said Jennifer Reidy, Howard County police spokeswoman. "We don't see an elevated [crime] rate there. People use [the trails] all the time to get to friends' homes or to the library."

Or, on a recent sunny Sunday afternoon, to run two miles and walk two miles and "talk to God," like Ellis Parker of Columbia.

Or to buckle on skates and glide lightly down a forest path like 9-year-old Jennifer Murphy, her father, Mike, far behind her, trying to keep up.

Wanda Gibbs, left, and James Walker stroll around Lake Elkhorn as Tim Witting and Joe Ahrens, far right, look for a spot where the fish are biting. A group gathers for a picnic under a gazebo along the trail on a Sunday afternoon. The 93-mile pathway system is an integral part of Columbia.A young rabbit and a swan in Lake Elkhorn, below, give visitors a glimpse of nature. Jennifer Murphy, 9, skates around Lake Elkhorn while her father, Mike Murphy, trails on foot. The pathways connect Columbia's 10 villages. Barbara Kellner of the Columbia Archives shows a 1971 Time magazine ad that used the pathway system to help sell Columbia.