The peanut-butter spread of unprecedented development is the underlying issue confronting Rockville city residents who go to the voting booths Tuesday to choose a mayor to guide them through the next two years of predicted boom growth.

The sprawl already has turned Rockville Pike -- the community's main street -- into a snarled linear parking lot, and builders are looking to scrape the city's skyline to house more businesses and a growing population.

In a city where progress is measured in traffic jams, Rockville Pike, a bulging, six-lane stretch of Rte. 355 lined with shopping centers, discount stores and gasoline stations, has come to symbolize the election. Although only half of "the Pike's" three miles are inside the city limits, Rockville's three mayoral hopefuls are running their race on that road.

Incumbent Mayor Viola D. Hovsepian, 62, and 37-year-old challenger Steven Van Grack both have proposed concrete solutions to Pike problems. John G Tyner, 48, who is trying to parlay seven years on the City Council into the mayor's post, has taken a wait-and-see attitude.

Tyner said the recommendations of the Pike Advisory Committee, convened 2 1/2 years ago, will provide a blueprint for relieving congestion.

Tyner has called for maintaining a balance between "the needs of the community as a whole and the needs of the business entitites that have an investment along the Pike."

Hovsepian, appointed a year ago to fill the unexpired term of former mayor John R. Freeland, said the answer lies in van- and car-pooling, public transportation, shuttle buses, upgrading arteries other than the Pike and encouraging a mix of development.

"More traffic is added to our street and highways unless housing opportunities are close to job opportunities. Housing can be physically close or close in the sense of having convenient public transportation nearby," Hovsepian recently told The Washington Post.

For Van Grack, solutions to the Pike problem lie in shuttle bus services, sidewalks and footbridges over and around the thoroughfare, better timing of traffic lights and simpler access to the Pike's maze of shopping centers.

His informal campaign slogan, underscored last Monday in a two-mile race on the Pike against rush-hour traffic, is "Nobody walks across Rockville Pike -- some people run and some people dodge."

Off the Pike, buried in the center of Maryland's second largest city -- and in the memories of many of the longtime residents among its nearly 44,000 population -- is a charming, walking-scale city that is eroding amid commercial encroachment.

Many of Rockville's 9,446 registered voters are looking at leaders to meld modern development with preservation of the best of the formerly quaint county seat in a race that pits residential concerns against commercial ones. Underpinning the race is the question: Is Rockville a place to live, to work, to shop or to do all three?

"Rockville is right in the middle of three major highways -- 355, 270 and Veirs Mill. It all comes back to development, but it's not easy to talk about the quality of life when the quality of life is under siege by these three corridors," said Lisa W. Taylor, 54, a real estate agent who has lived in Rockville since 1971 and is the president-elect of the 650-member Rockville Chamber of Commerce.

"The blight . . . is not even within city limits. In Rockville, north of Twinbrook, you have trees, you have service drives, you have set-back signs. You go south and you have crap," Taylor said. "Instead of being a linear parking area and Montgomery County's shopping mall, we're trying to bring back the charm. At least it isn't lost; it's there for people to discover."

Hovsepian and Van Grack both contend it's time to slow down on wooing business and try to attract families to live in Rockville.

Van Grack said that if city leaders had highlighted residential rather than commercial growth during the past decade, the city would not be facing lack of population that threatens to close Richard Montgomery High School because not enough students are enrolled there.

Hovsepian maintains that people need more places to live in Rockville if the city is to grow in harmony with jobs and services. "We now have more than two jobs for every household in the city and in a few years we'll have more than three jobs for each household. That means we need to look at innovative ways of providing housing," Hovsepian said yesterday.