Earning your flagger certification is only one of many things you need in order to be able to do the job of a flagger in a work zone. Here are the physical requirements set out by the MUTCD, Section 6D.01:

Because flaggers are responsible for public safety and make the greatest number of contacts with the public of all highway workers, they should be trained in proper traffic control practices and public contact techniques.

Flaggers should be able to satisfactorily demonstrate the following abilities:

A. Ability to receive and communicate specific instructions clearly, firmly, and courteously;
B. Ability to move and maneuver quickly in order to avoid danger from errant vehicles;
C. Ability to control signaling devices (such as paddles and flags) in order to provide clear and positive guidance to drivers approaching a TTC zone in frequently changing situations;
D. Ability to understand and apply proper traffic control practices, sometimes in stressful or emergency situations; and
E. Ability to recognize dangerous traffic situations and warn workers in sufficient time to avoid injury.

Flaggers are usually also required to perform additional work zone duties, so they need to have the following physical abilities:

• Stand for prolonged periods on uneven surfaces (up to 10 hours)
• Traverse uneven surfaces and terrain
• Stoop, kneel, or crouch
• Grasp, push, or pull
• Hear warnings
• See dangerous situations
• Occasionally lift and/or move up to 40 pounds
• Receive, understand, and take positive appropriate action based on information/instructions presented verbally and/or in writing