Commuting for Chris Woerner once meant putting 12,000 miles on his pickup truck in eight months. Besides the wear and tear on his vehicle, the commute was taking a toll on him.

"I used to really get tense," says Woerner about the 66-mile round trip from his home in the Frederick, Md., area to the Bechtel Power Corp.'s Gaithersburg facility. "When there were other people riding with you and you were in heavy traffic, you'd feel the responsibility and really get tensed up."

When Bechtel started a vanpooling program, Woerner, 38, became a charter member. Besides relieving the internal pressure, vanpooling helped Woerner cut down mileage on his pickup to 6,000 miles a year, or about a third of what he once tallied. When he made the drive himself, he spent "$80 a month on gas alone." He pays $43 a month for vanpooling.

"This way, my truck is going to last me for awhile," says Woerner. "I just hate to make car payments."

Besides, he adds, the ambience isn't bad: quiet in the morning and sociability and snacks on the way home.

"It's really great. Our van has not missed a day since the pool started, no matter what the weather."

Woerner, dispatcher and maintenance chief, shares his enthusiasm for vanpooling with a rapidly growing number of other Americans. Figures from the 1980 census indicate that almost 1 in 5 Americans share a ride to and from their jobs, and in more than half the states more than 20 percent "pooled" to and from work. Virginia was one of five states where the number of poolers exceeded 25 percent.

Ed Marks, executive director of the National Association of Van Pool Operators, says there were about 14,000 van pools in operation nationwide in April 1981. "By the middle of 1982," he says, "that figure had gone up to anywhere between 18,000 and 21,000. With 20,000 van pools, you're talking about 200,000 commuters a day."

Among those sponsoring vanpooling nationally are the U.S. Department of Energy, United Airlines, Gulf Oil, Chrysler, Allstate Insurance and the Tennessee Valley Authority.

The 3M Corp. of St. Paul is credited with "inventing" company-sponsored vanpooling. What they started as a six-van pilot program in 1973 has grown to 150 vans.

Bechtel also has about 150 van pools operating nationally. They estimate their 80-van Los Angeles program represents an annual savings of 361,000 gallons of fuel and $760,000.

Charles R. Zimmerman, manager of office services for the Gaithersburg operation, claims that both the corporation and employes benefit from vanpooling -- Bechtel because of improved employe morale, less tardiness and absenteeism, conserved parking spaces and improved employe efficiency; the employes because of lower commuting costs, less stress and "they know they can leave work on time. They can say, 'Sorry, I have to catch my van pool.' "

Bechtel, says Zimmerman, subsidizes a portion of the operating expenses and does its own minor maintenance. Fees are based on number of riders and distance of the commute. "They pay by payroll deduction, and the drivers ride for free."

Fifty vans now transport 550 to 600 of the 2,800 employes at the Gaithersburg facility. Zimmerman says they expect to have 75 vans in operation by the end of next year.

Besides company-sponsored van pools, there are two other basic vanpooling categories: third-party and owned-and-operated.

Third party -- Most often leases vans to drivers on a monthly rental basis. They also sometimes run the van pool for the lessee.

Phyllis Thompson, head of CPT & Associates, currently has 8 vans under lease in the Prince George's-Anne Arundel area. She charges "a nominal fee" for running the van pools. This setting up of the van pools is "a very labor-intensive business," she says. "It takes time and we like to give the drivers our personal attention. They are very important to us."

Thompson helps drivers find riders and replacements when a rider is sick or moves and generally acts as a sort of den mother. She says her drivers and riders alike are enthusiastic about vanpooling, and they have a good time:

"We had one group that decided they needed to have a fire drill. They all wore yellow slickers and gave the driver a hat with a siren on it. When the siren went off they all went piling out of the back. It caused quite a stir among the other drivers and commuters in the area."

Driver-owned-and-operated (o/o) -- By far the fastest growing program. The driver purchases the van and assumes all financial risk and responsibility for organizing and operating the pool and maintaining the van.

Vanpooling experts concede that it's possible to operate the pools on a for-profit basis but say it might be more realistic to look at o/o operations with a break-even goal. They cite high maintenance costs and erratic quality control at the factory as two reasons for reduced expectations.

A major selling point for vanpooling in the Virginia area is speed. Lew Pratsch, head of the third-party Transportation Total, Inc., and a former van pool manager with the Department of Energy, says 60 percent of the Shirley Highway commuters are using the high-occupancy vehicle express lanes.

"There's virtually no congestion in those lanes," says Pratsch. "The 40 percent driving to work in the regular lanes are bumper-to-bumper and continually backed up."

In 1978, Pratsch says about 80 van pools were operating on Shirley Highway. By April of 1982, that figure had more than quintupled, to 465. "I counted it as a van pool," he says, "if it had at least nine people in it."

Pratsch points out that route I-66 inside the Beltway will be reserved for high-occupancy vehicles when it opens "late this year or early next." From a commuting standpoint, Pratsch says, "I'd rather live in Northern Virginia than in any other fast-growing community."