A single building on a site is straightforward. Drop it, orient it, connect it to the street. But when a project involves multiple buildings, the design challenge changes. Every structure now has relationships with every other structure, with the site's edges, with pedestrian and vehicular networks, and with the surrounding neighborhood.

Site adjacencies define which uses need to be close together and which ones need separation. A campus dining hall should sit within walking distance of residences. An industrial maintenance facility should be buffered from classrooms. These aren't arbitrary preferences. They shape how people move through a site, where conflicts arise between vehicles and pedestrians, and how efficiently infrastructure serves the whole development.

For PPD, NCARB expects you to determine the location of buildings and site improvements based on adjacencies, planning concepts, and site analysis. That means evaluating trade-offs. Should compact development reduce infrastructure runs but increase density conflicts? Does a connected street grid improve wayfinding while complicating service vehicle access? Can transit-oriented placement reduce parking demand without creating pedestrian bottlenecks?

The principles in this topic apply to campus plans, mixed-use developments, military installations, healthcare complexes, and institutional grounds. The scale varies, but the analytical framework stays the same: understand the functional relationships, map the circulation hierarchies, and arrange buildings to serve both current needs and future flexibility.