A Palo Alto law that requires new development to be built close to the street may soon be scrapped or modified, though officials remain far from certain about what type of changes should be made.

The city's Architectural Review Board on Thursday considered a proposed elimination of what's known as "build-to line," a requirement that seeks to create an "urban edge" by mandating that buildings along major thoroughfares be within 12 feet of the street. When it was created, one of the rule's main objectives was to prevent developers from putting parking lots in front of their properties on major thoroughfares such as El Camino Real and Middlefield Road.

From the perspective of many residents and most council members, the rule worked a little too well. In the last few years, the council has been fielding concerns from the community about dense new developments such as 801 Alma St. and Arbor Real, which critics argue are far too massive and close to the street. In April 2013, council members Karen Holman, Greg Scharff, Gail Price and Greg Schmid penned a memo that urged staff to explore new rules that would encourage wider sidewalks and address community anxieties about buildings that "turn their backs on the public right of way."

But making these changes has proven to be a tougher task than most have imagined. The city's proposed "sidewalk ordinance," which applied to El Camino Real, ran into opposition from property owners and was ultimately rejected by the City Council. In July, members agreed to scale back the proposed changes and focus the new rules on the "build-to-line" requirement, which is generally seen as a relatively benign change.

The new proposal would entirely eliminate the requirement on all major thoroughfares except El Camino Real, thus giving builders the option of creating greater setbacks without requesting zoning exemptions from the city. On El Camino, the rule would be relaxed and applied based on context. Buildings would no longer have to have an "effective sidewalk" of 12 feet. The majority of the building's frontage would have to be within zero to 10 feet of the street property line, though the requirement is no longer seen as a fixed "line" but rather as an "area" in which the developer would have flexibility to get creative with the building's alignment.

Placement of the building's frontage on El Camino would be based on context "including land use, adjacent and nearby properties' existing building setbacks, proposed or adjacent building design, lot size and similar consideration," according to a staff report from Chief Planning Official Amy French.

"The goal would be to allow more variable placement of the El Camino facing wall and minor changes in alignment on the street wall from one site to the next," French wrote. "In this way, the urban design intent of the build-to requirement would be retained, but the restrictive language would be loosened."

But while the latest proposal is far more modest than the prior sidewalk ordinance, board members struggled on Thursday to determine whether it's the best solution for assuaging local anxieties. The board also heard from two property owners, Ben Cintz and Sal Giovanotto, as well as attorney Andrew Pierce, who represented a group of property owners. Though none of the speakers took a stance against the ordinance, all had questions about the effect the new rules will have on El Camino Real. Pierce said the group hasn't taken a position on the new ordinance but stressed that "any requirement for an effective sidewalk that is wider would be unconstitutional" and would constitute a "taking" of land from property owners.

Board members had their own concerns about the change, with some arguing that the flexibility built into the ordinance effectively makes the rules less clear. Chair Lee Lippert suggested that the city's effort to change the sidewalk rules has been hampered by miscommunications, with many property owners feeling like their properties will be impacted.

"It comes across that we're imposing a taking where in fact what we're trying to do is be a bit more liberal or flexible in terms of what we're providing or trying to do here," Lippert said.

He proposed including in the new rules incentives for property owners who are willing to include wide sidewalks as part of new developments. This could include allowing greater height, he said.

"Whatever we do has to be communicated in a clear and concise way and done in a way that people don't feel as though the city is reaching into their pockets and taking from them," Lippert said.

Vice Chair Randy Popp said he was concerned about the "piecemeal" approach that the city has taken to revising its sidewalk rules. Adding controversial incentives such as greater height allowances would "kill the discussion," he said, which is "exactly what the council was trying to avoid" when it asked staff to narrow its revision effort. He acknowledged that El Camino has a wide variety of properties, many of which are shallow or narrow and said he was concerned about the prospect of someone aggregating 10 parcels on El Camino and building parking lots that create a "big gap" on the thoroughfare.

Others argued that the cautious approach makes the ordinance too vague. Board member Alexander Lew said the new ordinance has "the right intent" but stressed that "for the people who are concerned about big walls on El Camino, this will not be reassuring." The nuances in the ordinance make it "not digestible to a lay person."

Board member Robert Gooyer called the ordinance "a step in the right direction" but also said he was worried that the new rules create too much of a "gray area."

"Sometimes flexible also makes things more gray," Gooyer said.

People are often happier, he said, when the rules are clearly stated and do not depend on vague concepts relating to context.

"How it's implemented is going to be tough because of the flexibility," Gooyer said.

The board is expected to further discuss and vote on the proposed ordinance on Sept. 18. After that, the proposal will go to the Planning and Transportation Commission and, ultimately, the City Council.