The blue-and-gray tractor-trailer pulls out of the Overnite trucking terminal on Mooreland Avenue and quickly picks up speed as the driver furtively scans his mirrors to see if he's being followed.

He is.

Easing his tan Cadillac into traffic, striking Overnite driver John Culbertson pulls within 50 feet of the truck--the minimum distance under a court restraining order obtained by the company--ready to react to any move the truck might make to lose him.

For the next two hours, Culbertson and the two Teamsters pickets in the car with him will play a cat-and-mouse game with the Overnite driver, following the truck from one drop-off point to another and setting up an instant picket line aimed directly at customers who continue to use Overnite.

The scene is being replayed a thousand times a week at Overnite terminals throughout the country in a labor dispute that has fast become the battlefield in a test of strength between the International Brotherhood of Teamsters and Richmond-based Overnite Transportation Co., the nation's largest non-union trucking company.

The tactic being used by Culbertson and his fellow drivers around the country--ambulatory picketing--is one of the oldest in the labor relations rule book. It is a legal maneuver just this side of a secondary boycott that allows the union to legally picket the customers of a struck company any time a driver from that company shows up at the customer's door. Drivers from other unionized trucking companies are free to honor the picket line.

Ambulatory picketing can have a major impact when it interrupts deliveries, a situation intolerable to customers in today's world of just-in-time deliveries, when companies have little or no inventory to fall back on. Lost deliveries are often lost sales.

The 10-week strike against Overnite has also become a test of newly elected President James P. Hoffa's pledge to restore the Teamsters' power in an era of labor decline. "I will not sit by and watch our union's greatest treasure and my father's greatest legacy be destroyed," said Hoffa, the son of the infamous Jimmy Hoffa, who in the 1960s herded the major trucking companies into a single national contract, an act critics warned would give the Teamsters leader the power to shut the nation down.

Today, the younger Hoffa wants to rebuild the Master Freight Agreement in an industry where unionized trucking companies have been decimated by federal deregulation over the past 20 years. Since the trucking industry was deregulated in 1980, dozens of unionized trucking companies have gone out of business at the hands of new, non-union truckers with lower labor costs.

If he can organize Overnite, Hoffa hopes the rest of the industry will realize that the Teamsters are back. "It's a message basically to the trucking industry that we want to organize the industry," Hoffa said in a recent interview. "There hasn't been an effort like this for 20 years in the trucking industry."

To drive that message home, however, the Teamsters must first win at Overnite--a fight the company claims it's winning, but at an admittedly heavy cost. Company officials say there could be a 40 percent drop in profit for the year, most of it the result of extra expenses in preparation for the strike, which began Oct. 24.

The actual cost of the strike in terms of lost shipping is far less, according to Overnite officials. Through the end of November, Overnite said, there has been a 9.6 percent drop in shipments and a 2.2 percent revenue drop.

"It's had an impact, but it's been minimal," said Overnite Chairman Leo Suggs, who came to the Richmond-based trucking company two years ago after years of running two Teamsters trucking firms, Yellow Freight and Preston.

Suggs defends his company's resistance to the Teamsters' organizing efforts, saying the union's contract demands do not give Overnite the operational flexibility it needs. "Unionization in traditional terms would, over time, put this company out of business," Suggs said. He said the Teamsters' Master Freight Agreement would result in substantially higher costs for Overnite, with little or no return to the company in the form of improved productivity.

It's a notion Hoffa scoffs at, pointing to the fact that the major unionized companies, such as Yellow, Roadway and Consolidated Freight, are all making money today. The unionized companies, however, have also formed non-union subsidiaries, much as employers have had for years in the construction industry, and are trying to build their new non-union businesses.

Overnite spokesman Ira Rosenfeld candidly admits that the publicity campaign the Teamsters have mounted against the company, a tactic known in the labor movement as a corporate campaign, is hurting. "The biggest problem we face is the corporate campaign," he said.

It's hurting enough that the company has filed a defamation suit against the union, claiming it is spreading false statements about the impact of the strike, the number of people striking and the impact on customers. The company and the union can't even agree on how many people are striking and at which of Overnite's 166 terminals. They also can't agree on how many of the terminals have been organized by the union; the company acknowledges 22, while the union claims 37.

There are so many charges and countercharges flying through the National Labor Relations Board that even Hoffa admits he's not quite sure of the accurate numbers. But one thing both sides know is that the NLRB has certified this as an "unfair labor practice" strike, which means Overnite is potentially liable for millions of dollars in back pay to striking workers if the union wins.

There is another impact from the strike. The Union Pacific Co., which owns Overnite, has put the trucking company up for sale. But so far there are no active bidders, according to Suggs. The prospects of a sale in the midst of a major labor dispute appear dim.

The Teamsters' campaign against Overnite combines some of labor's oldest and newest organizing tactics and underscores a shift back to the streets by organized labor in its stepped-up efforts to win new members.

At the heart of the Overnite campaign are Overnite's customers. The goal of the union is to make customer dealings with Overnite so disruptive that they either drop the company or tell it to go somewhere else until it resolves its problems with the union. This was a key tactic of Hoffa's father in putting together the Master Freight Agreement; it was a tactic used by labor in the 1960s and 1970s, when it would enlist the support of consumer groups to picket retailers who sold struck goods; and most recently it was a tactic used by the Service Employees International Union in its successful "Justice for Janitors" campaigns.

Labor economist Thomas Kochan of the Massachusetts Institute of Technology said that in today's strikes, "the leverage now is really the customer. All the demands for speed from the customers and the ability to provide reliable, speedy service has just escalated in importance relative to saving costs." He predicts the focus on the customer will only increase as labor becomes more militant in its efforts to organize.

Last week, Hoffa gathered 1,500 protesters in New York City to announce a nationwide boycott of Bed Bath & Beyond, one of Overnite's major customers, as part of the escalating focus on customers.

With the tight shipping market at this time of year, there is really little the company can do about Overnite even if it wants to. There is simply no excess capacity in the trucking industry at the moment. The Teamsters know this but hope Bed Bath & Beyond will seek other trucking companies when its Overnite contract expires early next year.

It is that focus on customers that has Culbertson, 46, a 19-year veteran at Overnite, out on the road early on a December morning chasing a 40-foot-long tractor-trailer truck through the streets and highways of suburban Atlanta, ready to disrupt customer operations wherever the Overnite truck stops to make a pickup or delivery.

After pickets disrupt a delivery at a Goodyear tire center, the Overnite driver spends nearly an hour in a futile effort over back roads and highways trying to shake Culbertson before trying to do business at a warehouse terminal several miles away. The tractor-trailer weaves and dodges through traffic, often waiting at an intersection until the light turns yellow and then quickly driving on, leaving Culbertson confronted by a red light. But it's not easy to hide a 40-foot tractor-trailer.

At the warehouse destination, the stakes are higher than at the tire center, which has few big trucks delivering at the same time. The warehouse terminal receives major deliveries from other major trucking companies with Teamsters contracts, and these trucks won't cross the picket line as long as the Overnite driver is on the premises.

The moment the truck pulls into the lot, Culbertson is out of the car, walking toward the manager's office with a handbill explaining what the union's doing and the union's legal right to do it.

The handbill explains that the union is conducting an unfair-labor-practice strike against Overnite and has no disagreement with any company where Overnite is making pickups or deliveries. But, the flier says, the Teamsters have a legal right to picket the Overnite drivers. "We are picketing here only because the drivers and/or employees of Overnite are present." The implied message: As soon as you stop dealing with Overnite, the picket lines will come down outside your workplace.

The terminal manager says he told Overnite not to make deliveries and says he will tell the driver to leave.

Minutes later, Culbertson and the other two pickets are walking back and forth in front of the main terminal entrance when three young dockworkers emerge from a corner of the terminal and start walking toward the pickets.

"You've got one minute to leave or we're calling the police," shouts the leader of the group.

"Don't waste a minute, call 'em now. We're not leaving," shouts back Culbertson, a man who stands more than 6 feet tall and admits to weighing "300 something." He then begins to walk slowly in the direction of the dockworkers, who quickly retreat.

Within minutes the Overnite truck is quickly on its way again, back out on the highway, where the chase continues.

CAPTION: Democratic presidential candidate Bill Bradley, left, is applauded as he holds a picket sign with striking Teamsters last month at the Overnite Trucking facility in Moonachie, N.J.

CAPTION: Striking members of Teamsters Union Local 600 in St. Louis wave to passing trucks as they picket an Overnite facility in October. Union President James P. Hoffa sees the strike as a test of the Teamsters' ability to restore their power in a time of labor decline.

CAPTION: Overnite Chairman Leo Suggs says a deal with the Teamsters wouldn't work.