FIRE ACTIVITY AHEAD signs should be used when initial attack engines or crews are near a roadway. The FIRE ACTIVITY HEAD sign may be omitted if the incident vehicle or activity is behind a barrier, more than 24 inches behind a curb, or more than 15 feet from the edge of any roadway. For operations lasting less than 30 minutes, signs are not required if the incident vehicle uses activated high-intensity rotating, flashing, oscillating, or strobe lights.

Intermittent flagging operations may be needed to stop traffic when helicopter operations affect road users. Use the BE PREPARED TO STOP and the flagger symbol signs during all flagging operations. The advance warning sign FIRE ACTIVITY HEAD should be visible at all times, even when flagging operations are suspended.