In a modern rock group what is the job of the roadies?

The job of a roadie is to load/unload equipment for concerts and other forms of traveling entertainment (ie: circuses, traveling musicals, etc.). In addition to loading and unloading, roadies also set up the equipment and then break it down at the end of the performance. Some roadies may also have a specialty such as being a Guitar Technician or a Drum Technician. Roadies may also have additional duties that are determined by their employer.