Bonus or Incentive Zoning
Many communities will allow increased residential densities if developers include some units earmarked for low- and moderate-income tenants. For example, the law might stipulate eight units to the acre in a particular zone but permit an increase to ten units if 15 percent of the units are reserved for low- and moderate-income tenants. The developer gets the scale economies of denser development, and the community moves a bit closer to meeting its low- and moderate-income housing goals.
Many cities have made comparable arrangements with regard to office development. The zoning ordinance might stipulate a certain height limitation but permit additional height or stories if the developer will provide certain amenities at ground level (for example, a plaza in front of the entrance to the building, a direct entrance to a subway station, or a "vest-pocket" park or sitting area).
The two Greenwich Village streets shown here, though photographed in 2004, are very much as they were at the time that Jane Jacobs wrote. In the top photo, there is an off-Broadway theater on the left and a restaurant on the right with a small apartment house in between and apartments over both commercial uses. Access is overwhelmingly pedestrian, since the street that serves the neighborhood is narrower than would be permitted in even the smallest modern suburban subdivision. In the lower photo, note the mix of structure types and the stores under the apartments.