This accident occurred as Unit 1 was travelling west on Creek Rd. Opr 1 failed to negotiate a curve in the roadway. Unit 1 crossed the east bound lane of travel and onto the south berm where the vehicle went through a fence. After impact with the fence, Unit 1 continued travelling in a southwesterly direction where the rear drivers side of Unit 1 impacted a tree. Unit 1 continued down an embankment and came to rest in a field.