Merchants on California Avenue are well-versed in the typical challenges of running a business in Palo Alto: the high rents, the traffic jams and the lack of housing for their employees.

But there is one problem that for many rises above the rest: the district's insufficient supply of parking. And as the city moves ahead with construction of a new parking garage on Sherman Avenue, they are calling for officials to think big.

That was the main message that about 30 business people delivered Wednesday morning after hearing a presentation from Michael Ross, the project architect, and staff from the city's Public Works Department. After being presented with three possible design options for a new garage, the majority opted for a fourth, which would provide even more parking spaces than any of the alternatives on the table.

If things go as planned, the city would launch construction of the new garage next year and complete it in 2019, just before it begins construction on a new public-safety building near to the garage. Both facilities would be located on Sherman Avenue where currently there are parking lots.

Currently, the two lots have 310 parking spots between them, Ross said.

The first option presented Wednesday would create a garage with 471 spaces. Because 12 of the spaces would be designated for visitors to the public-safety building and 20 would be tied to the building's ground-floor retailers, the net gain in this scenario would be 129 parking spaces, Ross told the group.

The garage in this option would be a three-story building with a partial fourth floor and two levels of underground space.

The second alternative would stretch out the fourth floor and raise the parking capacity to 552 spaces, or a net gain of 210. Like the first option, it would feature retail on the ground floor, consistent with direction from the City Council.

The third option would eliminate the retail space entirely and dedicate all three above-ground floors to parking. The proposed garage in this alternative would feature one underground level rather than two. The net gain in parking spots would be 180, Ross said.

In coming up with the alternatives, the project team tried to balance a series of competing interests, which include the need for parking, the council's desire for retail space, zoning requirements and aesthetics.

"The news is positive. There will be parking," Ross told the crowd. "The question is: How much more parking?"

For the dozens who attended the Wednesday meeting, the answer was simple: As much as possible.

"We have concerns and the concerns all go by one word: parking," Jack Morton, president of the California Avenue Business Association, said at the onset of the meeting. "Roughly between 11:30 (a.m.) and 2 to 2:30 (p.m.), it's impossible to park here."

Most in the audience agreed and urged the city to pursue a fourth option. This would entail a three-level garage with no retail -- much like in Option 3 -- but with two basement levels rather than one. At the end of the meeting, when audience members were asked to mark their preferred options with green stickers, Option 4 had far more support than any of the others.

While council members have favored including a retail component in the new garage, business owners weren't too keen on this idea. Lara Ekwall, co-owner of the California Avenue restaurant La Bodeguita del Medio, urged city officials to consider the changing nature of retail before they move ahead with mandating a retail operation in the Sherman Avenue district. (The retail space proposed in Options 1 and 2 would be 4,700 square feet.)

"I'm worried our retail districts are going to evolve in five to 10 years into service districts where we'll have cobbleries and restaurants, but retail is going down," Ekwall said.

Rather than investing energy in bringing retail to this particular garage, the city should look at making the district sustainable "as a whole."

Others raised concerns about the impact of construction. Peter Katz, owner of The Counter, cited other recent neighborhood disruptions, including new buildings and the city's recent streetscape project on California Avenue. Businesses won't be able to survive a year or longer without having parking spaces that their customers and employees can use during construction.

Katz also recommended dedicating some parking in the new garage -- potentially on the top story -- to employee parking.

The California Avenue garage is one of two parking facilities currently in design phase. The City Council also has approved moving ahead with a new downtown garage, which would go up on a parking lot at Hamilton Avenue and Waverley Street. Both facilities -- along with the new police building, the proposed bike bridge over U.S. Highway 101 and replacement fire stations at Rinconada and Mitchell parks -- are included in the council's infrastructure plan, which was approved in 2014 and is funded by revenues from the hotel tax.

Brad Eggleston, assistant director of Public Works, acknowledged that while some funding has been allocated for all these projects, it likely won't be enough to meet the full cost.

"We know that more funding will be needed but we don't have those funding numbers yet," Eggleston said.

Costs will undoubtedly play a greater role in the discussion on April 3, when the council is scheduled to discuss the new California Avenue garage. But for the business owners like Ekwall, the bigger priority is maximizing the number of spaces that the new garage would provide.

"This isn't going to happen again for California Avenue, so we need to make sure we get as much parking as possible," Ekwall said.