Construction of an interchange at I-270 and Rte. 189 in Rockville is at least two years away from approval, but the proposal has already aroused heated controversy between area residents and the city of Rockville.

The Maryland State Highway Administration recently began a study of the proposed Falls Road-270 interchange, which Rockville officials and merchants say is needed to relieve congestion on interchanges and roadways leading to the central business district. But residents of the area claim that the interchange is only an attempt to develop downtown Rockville and will destroy the quiet suburban character of their neighborhoods.

The Highway Administration has begun analyzing area traffic patterns, examining construction alternatives and evaluating the impact the interchanges would have on the surrounding area, according to state highway administrator M.S. Caltrider. This phase of the study is expected to take 18 months to two years to complete, Caltrider said.

Within three to five months, the Highway Administration will begin scheduling public meetings on the plan, with public hearings expected to begin in about a year, Caltrider said. If the studies confirm the need for an interchange, construction could begin in fiscal year 1983. No cost has yet been determined, but if approved, the interchange will be funded 90 percent by federal funds and 10 percent by state funds.

While Caltrider noted that the study will simply "explore the feasibility of an interchange" and that construction "is not a foregone conclusion," Rockville officials say they are counting on the interchange, which has been one of their priorities for the last decade.

"The City of Rockville has been trying to persuade the Federal Highway Administration to construct an interchange for several years," noted Rockville City Manager Larry Blick. "The mayor and City Council are strongly in favor of it and are urging the state to accelerate the construction schedule if possible."

The interchange is needed for safety and to ease the traffic flow in and out of Rockville, Blick said.

"West Montgomery Avenue (Rte. 28) is overloaded, and it's not fair for that part of the community to bear that heavy a burden," he said. "If the Falls Road interchange is built, that would provide added justification for widening Falls Road which, as it exists now, is pretty unsafe.

"Also the county office complex and new circuit court now under construction will be in operation in September 1981. This interchange will be critical for those people across the county who want to visit and do business at the courthouse."

Many Rockville merchants also favor the interchange. "Anything that will ease the problem of getting people in here and out, I am for," said Robert T. Gring, general manager of the Commons at Courthouse Square, the new name for the $14-million Rockville Mall.

The mall has had financial problems since it opened in 1972, and some merchants have called it a real disaster area.

The Commons is still operating in the red, with a 10 percent vacancy rate Gring, the center's fifth manager in six years, noted that that is an improvement over the 30 percent vacancy rate the shopping center had in December 1977.

"Anything that's going to bring more traffic is going to help us," echoed Mary Belle Peter, president of the Commons Mall Merchants Association.

But residents near the proposed contruction have little sympathy for the merchants and call the planned interchange "obnoxious" and "unnecessary."

"We feel it would be a dreadful thing that would change the character of our neighborhood," said Bobbie Kestenbaum, who helped organize eight local civic groups into the Coalition for Falls Road when she first heard of the proposal almost two years ago.

"We don't want to encourage the use of Falls Road for outside commuters because as traffic grows they'll seek to make it a four-lane divided highway. Building shopping centers won't be far behind."

"We're violently opposed to it because in a very short time we in Fallsmead will be landlocked in a concrete maze," said Jim Cagley, president of the 265-family Fallsmead Homes Corporation.

"The best reason for the interchange is to develop downtown Rockville, and who cares about that?" Cagley asked. "We moved out here because it's a nice quiet place, and we're concerned that our citizens will be living in a concrete jungle."

The Fox Hills West Citizens' Association polled its 550 families last fall and found that residents opposed the interchange, according to association president John Tarpey.

"Falls Road is a country-type service road for the people who live here, and we don't feel it should be turned into an arterial highway," Tarpey said. "We don't oppose the study, but we hope to be able to convince them that the traffic and road network doesn't require the interchange."

Peter Hahn, president of the Mid-County Citizens' Association, which represents more than 1,000 families, noted that there already are two interchanges - Rte. 28-270 and Montrose-Road-270 - near the proposed construction. The Rte. 28-270 interchange, he said, is less than a mile from the proposed interchange; the Montrose-270 interchange, a little more than a mile.

He added that he questions whether taxpayers' money should be used to build an interchange that would primarily benefit downtown Rockville.

"I don't see it as our responsibility to support an interchange designed to save a poorly planned mall," he said.