Next time you're trying to cross the Woodrow Wilson Bridge and the traffic is backed up for miles by repair work, pause a minute to think about Frederic Lang.

Fred Lang invented the cables that are used to make the prestressed concrete panels now being installed to replace the dangerously damaged roadway on the Wilson Bridge.

The backups on the bridge are nothing compared to what's happened to Lang since the U.S. Patent Office issued him Patent No. 3,546,748.

For 12 years, Lang has been trapped in the traffic jam of the patent system, caught in a legal gridlock that he says has cost him half a million dollars in lawyer bills and forced him to sell a 40 percent stake in his invention to avoid losing it all.

"In the last 12 years, I have come to believe that the patent system is a hoax perpetrated on inventors," Lang says. "In comparison to patent procedures in some foreign countries, the U.S. Patent Office is ineffective and archaic. Our system inadvertantly helps to enrich the legal profession, because the law allows patent validity questions to be retried ad infinitum."

Only recently has he won decisions in U.S. District Court in Alexandria and in Delaware upholding his patent. Another trial is set for early next month to determine how much money Lang is owed for alleged patent infringement by VSL Corp., the Virginia engineering firm using his device on the Wilson Bridge.

Lang has another 15 lawsuits pending in his one-man legal battle with the prestressed concrete industry. But with two courts ruling in his favor, he can finally contemplate collecting royalties on his widely used innovation.

He may ultimately collect as much as $30 million. But that's getting ahead of the story. First, a brief engineering lesson:

The concrete beams and girders widely used in building and bridge construction gain much of their strength from steel reinforcing. Solid steel bars once were used, but since the 1950s, cables have been embedded in the concrete.

In a process called post-tensioning, the cables are strung the length of a beam-shaped mold, then concrete is poured around them and allowed to harden. Once the concrete has set, the cables are stretched and tightened to create compression that gives the beam added strength.

The reinforcing cables used to be wrapped in a layer of grease and a spiral of heavy paper before the concrete was poured. The paper had problems. It tore easily in shipping. The grease leaked, staining the concrete. Heavy concrete pressed through the paper and grease and clung to the cable, making it difficult to tighten.

Several improvements on paper wrappers were tried: putting the cables in ducts, wrapping the cables in plastic spirals, fitting loose sleeves around the cable. Lang, a mechanical engineer, suggested coating the cables with a layer of grease, then covering the grease with a tight-fitting seamless plastic coating much like the insulation on electrical wiring.

It worked. The plastic covering protected the cable from damage and reduced friction between the cable and the concrete, making tightening easier.

Lang filed for a patent in March 1972, set up a machine to extrude grease and plastic around a steel cable and began negotiating licenses to other companies to use his invention. Lots of them used it -- Lang estimates more than 1 billion feet of plastic-coated reinforcing cable has been made -- but almost no one has paid for that right.

Even after Lang got his patent in 1972, they argued that he hadn't really invented anything new and claimed other people had thought of the same thing first. Another inventor filed for a patent on the same product. Other companies started making plastic and grease-coated cable without paying Lang a penny.

Fred Lang began a long and costly battle that left him indebted and embittered about the nation's patent system and the rights of independent inventors.

"Right now I would not bother to get a patent unless I had at least a million dollars to spend on enforcing it," he says. Rather than getting rich off an idea, "the inventor is more likely to lose his shirt."

Lang has won every battle in his patent fight and yet very nearly lost the war.

The rival inventor's patent application was rejected by the Patent Office, but that took almost three years, and then the rival appealed to the courts. Ironically, Lang won the case because the other inventor also ran out of money and gave up fighting.

Hoping to settle the issue once and for all, Lang tried to utilize a new patent office procedure created for just such disputes. It took the government another 3 1/2 years to uphold his claim and "reissue" his patent.

Stealing a patented invention is not a crime, Lang learned. In order to protect his patent against infringement -- and collect any money -- he had to file civil lawsuits against every one of the allegedly illegal users of his device.

It was not until 1979 that his first infringement case came to trial. Lang had sued a Delaware company because the Wilmington federal courthouse is only 12 miles from his home in Landenberg, Pa., and that was the cheapest place to go to court.

"I was then about $250,000 in the hole on this invention and I had a bunch of other inventions I wanted to get on with," he recalled, noting that he couldn't have kept going that long except that "I got lucky on some real estate."

Lang's legal fees were then running $30,000 a month, and the lawyers said it would cost him $500,000 to win his war of attrition. Forced to plead to postpone the trial because he couldn't afford to go to court, Lang put his invention up for sale.

After several buyers turned him down, the inventor found an entrepreneural patent law firm that offered him a deal: They'd take his case on a contingent-fee basis in return for a 40 percent share of his patent.

Figuring 60 percent of something was better than 100 percent of nothing, Lang took the deal. It took three more years to win his Delaware case in a ruling handed down last April.

But a District Court decision sets no legal precedent, so Lang then had to file separate civil lawsuits against every other user of his invention. He found 16 of them, and sued them in 16 different federal courts.

So far, he's winning. Judge Albert V. Bryan Jr. ruled in Alexandria that VSL "willfully infringed" on Lang's patent. That means VSL not only must pay for using the invention, it could be required to pay triple damages. VSL did not return a phone inquiry on Friday.

Even Judge Bryan's decision does not end the local litigation, however, for the patent law system requires a separate trial -- set for next month -- to determine the amount owed the inventor. During the first trial, VSL said it has made 30 million feet of the product, which sells for 35 to 40 cents a foot. Lang is asking a 5 percent royalty.

Lang bitterly contrasts the dozen-year delay in collecting on his invention here with his experience in Japan.

Under the Japanese patent system, he says, the patent issuing process becomes a full-blown trial on the invention. Japanese companies raised all sorts of legal objections to his patent, but once it was issued, two big Japanese users agreed to pay royalties on his invention, and the matter was over.

Their more efficient patent system, Lang contends, is one of the reasons the Japanese are outperforming the United States in high technology.

If you don't believe the Japanese are winning, just count the Toyotas, Datsuns and Hondas some day when you're caught in a traffic jam waiting for Fred Lang's cables to be installed on the Woodrow Wilson Bridge.