Flag measurements are 12" vertical x 18" horizontal.
As for colors:
Blue = Lead Vehicle
Black and white = Convoy Commander
Orange = any vehicle in convoy not marked by other flags
Red = Hazmat vehicle ( gasoline, ammunition, anything that goes boom in case of fire)
Yellow = disabled vehicle
Green = last vehicle in convoy
Front and rear vehicles should also have a orange rotating or flashing amber light in top if traveling at night. Lead vehicle should have yellow sign affixed to front bumper with 4" block letters with words that say "CONVOY FOLLOWS". Rear vehicle should have a similar sign affixed to rear of vehicle that says "CONVOY AHEAD".
Hope this helps.
Major Baird
North Carolina Minuteman Coalition.
