This report evaluates the efficiency of federal spectrum use, performing a study that compares the spectrum resources used by several alternative land mobile radio (LMR) system architectures employing trunked radio technology to the spectrum resources used by the current conventional LMR systems.  This study considered the 162-174 MHz federal LMR band in the Washington, D.C. area.  The Washington, D.C. area was selected because it represents a spectrally congested environment and the 162-174 MHz band because it represents the most heavily used federal land mobile frequency band.