American Football NCAA Rule 1-2-3-a and b
a. Limit lines shall be marked with 12-inch lines and at 24-inch intervals 12 feet outside the sidelines and the end lines, except in stadiums where total field surface does not permit. In these stadiums, the limit lines shall not be less than six feet from the sidelines and end lines. Limit lines shall be 4 inches in width and may be yellow. Limit lines designating team areas shall be solid lines.
b. No person outside the team area shall be inside the limit lines. Game management personnel have the responsibility and the authority to enforce this rule. (Exception: Hand-held cameras under the supervision of the television partners may briefly be between the limit lines and the sideline after the ball is dead and the game clock has been stopped. This exception does not allow cameras to be on the field of play or in the end zone at any time.)