With all the traffic jams in this country, Philip Tarnoff is really getting somewhere.

When he founded Farradyne Systems Inc. of Rockville in 1984, Tarnoff planned to offer a range of engineering and implementation services for the telecommunications, traffic control and computer software industries.

But as the nation's roads have gotten more crowded, and as frustrated drivers have pushed local and state governments to alleviate the problem, Farradyne's traffic control business -- based mainly on the timing and monitoring of stop lights -- has become the company's bread and butter. Traffic control now accounts for about 85 percent of the private company's $3 million in annual revenue.

Now Farradyne is poised to take advantage of a new market within the traffic control industry that has attracted the attention of such large corporations as American Telephone & Telegraph Co. and Texas Instruments Inc. -- namely, intelligent vehicle highway systems, or IVHS.

An IVHS program uses elaborate monitoring, telecommunications and software systems to broadcast information about traffic congestion and related problems to drivers in their cars. Farradyne is one of a few companies in the country that has been involved with IVHS technology from the beginning.

The applications for this technology range from displaying road signs inside cars, to alerting rural drivers of stopped vehicles ahead, to helping commuters make better decisions about how to get to work.

Farradyne, which employs about 45 people, has been a primary contractor for two Federal Highway Administration tests of IVHS underway in Los Angeles and Orlando, Fla.

"In Los Angeles, the purpose was not so much to design a commercial system, but really to evaluate how much people like having that kind of technology in their car," Tarnoff said. Although even the most preliminary results are not yet in, Tarnoff said at least 12 states are seriously considering testing similar systems.

Interest in this new field has been widespread. The highway administration believes easing congestion will improve road safety and air quality, and as part of its effort is researching a variety of high-tech automotive systems, including IVHS. The agency will get $21 million from Congress for this research in 1991, and is seeking $80 million for the following year, according to Norman Van Ness, the agency's director of traffic operations and intelligent vehicle highway systems.

The automotive industry also is pursuing IVHS, "because as congestion increases, people just aren't going to buy as many cars," Tarnoff said. "They are going to look for alternative modes of transportation." General Motors Corp. provided the cars for the Los Angeles and Orlando tests.

So with the blessing of government officials desperate to quiet angry commuters, time and money are being poured into researching IVHS, and all kinds of companies are looking for a way to get some of it.

"We're getting a lot of calls from a lot of companies that have been dealing in the space industry and the defense industry that are looking for new technological areas they might be able to contribute to," Van Ness said. Some, he said, may see it as a stopgap measure until the space and defense industries are again busy.

Van Ness said there are probably about six companies that have the same kind of IVHS capabilities as Farradyne, but he added that "many others ... come rather close."

He said, "They certainly don't have a lock on the market."

In face of such competition, Tarnoff is trying to maintain a balance between IVHS work and the firm's more traditional traffic control work, which includes the monitoring system -- but not the timing -- for Washington's 1,300 stop lights.

"Only 6 percent of the urban highway miles have any form of control," Tarnoff said. "So you think of the potential -- it's phenomenal."