The Redwood City Planning Commission unanimously approved a 471-unit downtown apartment complex with three building towers 10 stories high, but not before expressing concerns about a plan to make residents pay extra for parking.

According to the plan -- the first of its kind in the city -- tenants who use on-site parking spaces would have to pay for them, and those who don't use them wouldn't. Several commissioners said the problem with that approach is that some tenants who choose not to pay for garage space may end up parking their vehicles on nearby streets instead, to the exasperation of neighbors.

Regardless of who pays and who doesn't, the 599 parking spaces that will be provided for the complex at 525 Middlefield Road meet requirements in the downtown specific plan approved by the city council in 2011, Planning Manager Blake Lyon told the commission Tuesday night.

Commissioner Randy Tabing said he favors the overall project but is wary about its parking element.

"I don't want us to just fly by this decision without some forethought of what if something goes wrong," Tabing said. "That's my main concern, just because of the sheer magnitude of the project."

During the public comment portion of the meeting, Kevin Frederick, an attorney and one of the owners of a historic home used as a law office at 605 Middlefield Road, said a spillover of cars from the complex would "decimate the parking in downtown Redwood City."

In response to such concerns, commissioners suggested that as a condition of approval parking at the complex and on the streets should be surveyed at some point in the future and changes made if problems arise.

Developer Paul Powers said he would agree to going with a traditional "fully-bundled parking arrangement if it was found this wasn't working."

But commission chairman Ernie Schmidt said he wouldn't want some tenants to be told at a later date their rent is increasing to pay for parking.

"The unbundled parking is not a concern of mine because I think the individuals who are renting out these spaces are going to be paying additional money to park in the garage," Schmidt said.

In the end, the commission voted to approve the project without imposing the suggested condition.

Proposed for a 2.4-acre site bounded by Middlefield Road, Veterans Boulevard, Jefferson Avenue and Bradford Street, the apartment complex would include a swimming pool, spa, gym, recreation room, bike parking and a dog exercise area.

During his presentation to the commission, Powers pointed to the project's economic benefits, including $9.7 million in public improvement and impact fees to the city, about half of which would be allocated for parks. And compared to the annual $105,000 in property taxes on buildings now at the project site, the apartment complex is estimated to generate $2.1 million a year, with about 48 percent going to local schools, Powers said.

Several residents spoke out in favor of the project, telling commissioners that Redwood City could use the money as well as an influx of potential patrons.

"This project is going to finally bring the people to Redwood City and create the foot traffic that we need for all our businesses to be successful," said Fox Theatre owner Eric Lochtefeld.

Email Bonnie Eslinger at beslinger@dailynewsgroup.com; follow her at twitter.com/ bonnieeslinger.