Complex sentence: In North America, the Tahoe is used by many law enforcement agencies, fire departments, and EMS agencies prior to the announcement of the Z56 police package model the civilian base & LS models based on the GMT400 were used in police service.
Split into simpler sentences: In North America, the Tahoe is used by many law enforcement agencies, fire departments, and EMS agencies. Prior to the announcement of the Z56 police package model the civilian base & LS models based on the GMT400 were used in police service.