Those nagging issues of insufficient downtown parking and increasing congestion were already on Palo Alto's radar nearly three decades ago, when the city changed its zoning laws and set a cap on how much new nonresidential development it would allow downtown.

Though the limit of 350,000 square feet of new development that the city established in 1985 remains beyond the city's land-use horizon, a series of major applications has just brought downtown development to another plateau -- a 235,000-square-foot threshold at which the city must conduct an analysis of downtown zoning regulations and parking strategies.

The city edged toward this threshold thanks to two major downtown developments -- one that recently won the city's approval and another one that is about to make its way through the city's design-review process. The former, Lytton Gateway, is a four-story mixed-use development that the City Council approved in May and that will soon go up on the site of a former Shell station on Alma Street and Lytton Avenue. The latter is the proposed four-story commercial building that local developer Charles "Chop" Keenan plans to construct at 135 Hamilton Ave.

When the council approved the Lytton Gateway project, it raised the amount of nonresidential space approved by the city since 1985 to 212,000 square feet. Keenan's 26,000-square-foot project would officially send the downtown area over the study threshold.

The two new projects, coupled with the flurry of complaints from downtown residents about parking, have prompted the city to embark on the comprehensive analysis of downtown zoning regulations and parking policies. The analysis will include consideration of whether the "downtown cap" should be raised to a different level or kept as is, Planning Director Curtis Williams said. Under existing law, reaching the 350,000-square-foot cap would trigger a moratorium on approving new developments in the downtown commercial's zone, which stretches roughly from Alma Street in the west to Webster Street in the east and which is bounded from north to south by Lytton Avenue and Hamilton Avenue, respectively.

The study will also consider the upcoming project at 27 University Ave. -- a proposal by developer John Arrillaga that would include a new theater and office building on the current site of MacArthur Park restaurant. Though the project is technically outside the borders of the downtown commercial district, it is expected to further impact the area's parking and traffic.

The council approved the new study on July 16 as part of its approach to tackling the area's well-documented parking woes. Residents who live in neighborhoods adjacent to downtown's commercial heart have long complained about downtown employees parking all day in front of their homes. Residents in the Professorville neighborhood clamored for a parking-permit program that would set a time limit for visitors -- an idea that the council had considered but ultimately rejected last month. Downtown North residents, meanwhile, complained that the new Lytton Gateway project would further exacerbate an already acute parking shortage. Their complaints prompted a series of revisions in the project and a commitment from the project developers to contribute $2 million toward a new garage and $250,000 toward a broad study of parking strategies.

That study, which will consider new parking garages and new programs to encourage parking in existing garages, is just one of many components of the city's forthcoming downtown analysis. Planning officials will also take a close look at zoning regulations and consider whether the city's incentives for new developments and its parking requirements are sufficient. They will also consider the possibility of allowing denser development downtown, according to a report from Chief Transportation Official Jaime Rodriguez.

At the July 16 meeting, Mayor Yiaway Yeh said the actions that the city will take after the comprehensive study could "reset the baseline" downtown. Those dramatic changes could obviate any need for more immediate and geographically precise solutions like the permit-parking program advocated by many in Professorville.

The city also plans to take a closer look at the new ways in which offices are being used. Many startup firms, for example, eschew traditional offices and cubicles in favor of having more employees work within smaller spaces, such as gathering around a table with their laptops. That, in turn, affects the amount of parking taken up on the streets.

Existing regulations require office developers to provide one parking space for every 250 square feet of space, a ratio that Williams said is standard among planners. But that ratio may no longer suffice.

"Now, we're clearly seeing, at least in start-up spaces, ratios where it's at least one per 150 (square feet) or even less, and so those ratios are not as relevant as they were," Williams said in a recent interview. "That's something we'll look at as well. To some extent, it's operative all over the city, but it's particularly intense downtown because of the start-up concentration."

One idea is to have one parking ratio for startups and another one for more traditional businesses such as law offices or venture capital firms, which remain in compliance with the traditional model of office use. Another idea, Williams said, is to have "performance-based criteria" -- one that allows any business to use the existing ratio for parking spaces provided that it has a strong program that encourages employees to take public transportation rather than drive.

At the same time, the city also plans to start working with downtown businesses and with its own employees to shift them away from cars. One of the components that the study will include is the potential for a "downtown-wide transportation demand management program" that will rely on tools such as transit passes, shuttles, car-sharing and bike-sharing programs to reduce vehicle use.

"One of the things we want to do is develop something that the city itself can use, as an employer," Williams said. "Then we can use it as a demonstration tool to show the city is on board as well."