University Park officials suggested the Bush Foundation go back to the drawing board Tuesday and look for design options to move two proposed parking lots away from a nearby residential neighborhood.

Homeowners who packed City Hall burst into applause after Planning and Zoning Commission members said they were not satisfied that presidential library architects fully vetted all the options.

"If this is all there is, it's probably not good enough," planning commission chairman Robert A. West told lawyers representing the Bush Foundation. "Please take a look at it. We need more information before we make a decision and move this on to council."

Some homeowners who live north of the library site said the commission's action was a sign that their campaign has gained traction. They want to block the Bush Foundation's request to rezone land for the library until they get more commitments about the parking lots, as well as plans to handle traffic, particularly on days that Southern Methodist University is hosting multiple events.

"The commission definitely is listening to the neighborhood," said homeowner Tom Bowen.

Jim Harris, a lawyer representing the Bush Foundation in the zoning matter, sounded a conciliatory tone even before the commissioners weighed in.

"The concerns of our residential neighbors are also our concerns," Harris told the group, adding that the plans are "not static."

Harris came prepared to make some changes responding to concerns that were raised at a previous public hearing. He said SMU President Gerald Turner has signed a "letter of understanding" to provide space on campus when the presidential library needs overflow parking space.

And he said library architects have tweaked design plans to prevent drivers from looking for parking on residential streets when the lots are full. The lots would be heavily landscaped and "partially submerged" at a lower grade than the residential area and the library itself, he said.

But commissioners and residents said they believe the lots pose a safety hazard if they are located north of SMU Boulevard and pedestrians cross four lanes of traffic to enter the library, which will be south of the street.

Detailed design plans were unveiled last month and groundbreaking has been scheduled for late next year. It was not immediately clear what effect, if any, the zoning commission's request will have on timing.