I got an email from an Architect Colleague working on a infill project for a private developer across the street from the light rail station in a suburban city in the Northeast.  The City does not want to reduce the off-street parking requirement and does not think anyone would ever use ZipCar if the developer set up a couple spaces for ZipCars on the site.  My advice below comes from frustration with similar circumstances over the years.

Create two choices that are clear and straightforward.  Propose that by following the city's current 20th Century parking requirements and building Design "A" you can build 20 units next to transit.  You could call this "pretending that massive transit investment does not exist."  Design "A" produces $80,000 in annual property taxes for the city.

Design "B" delivers the amount of parking we think the market demands considering that the massive transit investment actual does exist and is a significant amenity for  the site.  You have further expanded the transportation choices by providing 2 zip car spaces based upon the projected usage by the folks at ZipCar.  Design "B" consists of two buildings and produces 40 units in a wider range of size and configuration and $160,000 in annual property taxes for the city.

The developer recognizes that the city may seek to delay its participation in the 21st Century for a few more years and if required to,  will limit construction to the over-parked 20th Century Design "A" and preserve a portion of the over-parked site for an additional building.  Eventually we expect that the city will want us to build the second building on the site and complete Design "B".

Don't fool around at the edges.  Present a clear choice.  If the  City picks the 20th Century Design you were never going to get much more than that, and I don't think you should not waste your time trying to make inconsequential marginal improvements on the over-parked design, (apart from preserving a portion of the site for more building, keeping the utilities out of the future building pad.)

If the City is going to value parking over more market rate dwellings next to transit and greater tax revenues, there is little chance you will convince them to do otherwise.  Build half of the buildings and go down the road to do something else.  Give them the numbers and the clear choice.   If they pick more parking and less tax revenue on purpose, the best you can do is save a place for another building for when more thoughtful people are in charge.

If the developer is smart they have not closed on the  land yet.  They can offer the seller less money now that they have discovered that the site is contaminated with a bullshit parking requirement and is inconveniently stuck in a 20th century time warp.

Those things just make the land less valuable.  Sorry.