From Utah Department of Transportation Flagger Training Handbook:
"The Utah Department of Transportation requires all flaggers to be
trained and to carry a Flagger Training Certificate. In addition to receiving the training an applicant must also meet age requirements established by the Utah State Labor Commission.
The Flagger Certification is good for a three (3) year period. The
flagger must attend a re-certification seminar and be
re-certified every three (3) years.
The Utah Department of Transportation is requested on occasion
to accept additional certification programs. The Department will
review each program, and each acceptable program will be listed
in the Utah Department of Transportation Standard Specification
Section 01554 Traffic Control.
Some utilities and other government entities conduct their own
training, the instructors for this training are certified by UDOT.
This certification is only good on roadways under UDOT jurisdiction, while working for the issuing entity. A flagger must receive a new certification from one of the accepted certification
programs before working for another employer.
All individuals who work at a flagging station must be
certified. The certification card must be on your person while
you are working on the roadway."
A list of certified flagger instructors are available on the web site below.