2013 California Standards for Accessible Design Pocket Guide

CARRIAGE UNIT. [HCD 1-AC]  A dwelling unit with living space on one or more floors immediately above a Group U, private garage or garages. The footprint of the garage or garages is used as the footprint for the remaining floor or floors of the units above and the garage level contains no habitable space.

Note:  Dwelling units located over a common garage shall not be considered carriage units.