The form and fate of downtown Silver Spring are soon to be determined by vote of the Montgomery County Council. One hopes that the council -- faced with mounds of data, contradictory contentions and unprovable theories -- is able to decipher them all and reliably predict the future, for much is at stake.

Critical amendments to Silver Spring's Annual Growth Policy have been proposed by County Executive Sidney Kramer. Among other things, the amendments would increase the statutory job ceiling in Silver Spring's central business district. Their ultimate effect would be to sanction substantial new square footage, most likely retail and office space.

Negotiating job ceilings hardly seems to be the way to establish or modify urban design and growth policy, especially when a specific plan exists. Indeed, in 1975 the council adopted the Silver Spring CBD (Central Business District) Sector Plan, which envisioned a high-density, mixed-use downtown. Amendments were anticipated to reflect changing circumstances -- for example, in 1975 there was a sewer moratorium and no Metro station.

Today's pending legislation is based partly on resolving conflicts in public policy. While the sector plan advocates revitalizing downtown Silver Spring through intense office, retail and residential development, the county's Adequate Public Facilities Ordinance requires that development be matched to infrastructure capacities -- roads, public transportation, utilities, schools. There is a mismatch now.

Proposed growth policy changes also would make Silver Spring a special transportation and parking management district. Coupled with a new job capacity, this would permit the sector plan's policies to conform with the public facilities ordinance.

But another part of the rationale for amending the plan has no legal basis. It stems from the widely held, if possibly mistaken, belief that Silver Spring's urban core remains depressed and neglected, and that pending project proposals represent one last window of opportunity for upscale development, an opportunity that will vanish forever unless it is seized now.

In particular, the linchpin proposal envisions a regional indoor shopping mall anchored by a pair of major department stores. The mall would stretch bridge-like across Georgia Avenue. To accommodate automobiles, the county -- or someone -- would have to build one or more large parking garages linked to the shopping center.

Not surprisingly, there has been considerable skepticism and no small amount of organized opposition toward these proposals. Mostly it has come from residents of neighborhoods in Silver Spring and Takoma Park. Preservationists concerned about the Art Deco Silver Theatre and shopping center at Georgia Avenue and Colesville Road also have expressed little enthusiasm for county policies and developers' aims.

Citizens have mostly focused on two issues. First, they are convinced that the proposed development will dump too many cars on already overloaded roads. Second, many are dubious about the economic and esthetic viability of inserting a regional shopping mall into the middle of downtown Silver Spring.

The transportation and traffic questions have generated the greatest debate, the largest collection of data and the most serious number crunching. Indeed, the numbers seem to have gained the upper hand. Having seen many of them, I'm still not sure where the truth lies, which is the dilemma confronting an undoubtedly befuddled County Council.

The transportation analysis supporting the sector plan amendment legislation makes a number of optimistic assumptions about current levels of traffic, future road network capacity and travel modes. It predicts that Metro will continue to account for a significant portion, about one quarter, of all trips in and out of the business district. It suggests that, given the district's special nature as a "downtown," marginal levels of traffic efficiency are acceptable.

Opponents challenge both the methods and the conclusions of the traffic analysis. They claim that the county's analysis, among other things, disregards potential traffic generated by pending and future development elsewhere, while underestimating current traffic volume and road network limitations. They insist that many Silver Spring intersections already operate at traffic level F -- on a scale from A to F, F being unacceptable.

Furthermore, many traffic-conscious citizens argue that downtown Silver Spring's overburdened arterials -- Georgia Avenue, Colesville Road and East-West Highway -- will push new hordes of commuters to seek alternative paths through adjacent, intimately scaled, occasionally historic neighborhoods.

Another area of debate concerns Silver Spring's character and image as a place to shop, work and live, along with its relationship to other commercial cores in the District, Montgomery and Prince George's counties. Several questions persist:

What kind of place should downtown Silver Spring become in terms of scale and size of development, type and location of retail activity, amount of office space, open space and housing?

Why has the retail component of development prescribed by the 1975 plan not been realized? Is Silver Spring really as moribund as some assert? Past and pending development activity suggest otherwise. Is the defunct Hecht's symptomatic of a malady in Silver Spring or just an isolated example of one poorly positioned, poorly maintained, poorly managed store?

Would a regional shopping mall, if built, succeed? Can it compete with other not-too-distant malls and shopping districts? Will people come, either by car or Metro, given other choices, including downtown Washington, via the subway's Red Line?

What would be a mall's impact, visually and socially, on Silver Spring's pedestrian streetscape? How can a suburban, internally focused, blank-walled structure be integrated into a downtown? Would it siphon off vital street life while wiping out, or economically precluding traditional service and convenience retail establishments -- from shoe repair shops to hardware stores to taverns?

Would a regional shopping mall in downtown Silver Spring really be nothing more than a kind of "loss leader," a retail facility built to justify, and perhaps be subsidized by, a new wave of office buildings?

Where is all the housing called for in the sector plan? How can public policy induce more residential development, which is needed to animate the business district, especially when economics has so clearly favored office development?

Most agree that the 1975 sector plan needs to be scaled back, that completely filling the central business district zoning envelope would lead to perpetual gridlock.

But how much is enough, and how much is too much? One gets the feeling that the latest visions for Silver Spring's downtown could become an amalgam of Rosslyn and an airborne Crystal City underground, with the shadow of Rockville's mall lurking about.

The County Council is being asked to engage in a crap shoot, responding apparently to specific now-or-never proposals. Perhaps the game should be slowed down, at least to allow the county's planners, along with other public and private parties, to scrutinize more thoroughly the Silver Spring sector plan and amend it accordingly. Guessing at numbers of jobs is a back door approach, and the resulting development may prove disastrous.

Roger K. Lewis is a practicing architect and a professor of architecture at the University of Maryland.