Whenever the quarterback is sacked, the clock will be stopped for at least five seconds and then restarted again.
If a fair catch is made, or signaled and awarded to a team because of interference, on the last play of a half, the period can be extended and the team can run one play from scrimmage or attempt a fair catch kick.
Defensive linemen can wear numbers 90 to 99.
Centers are included as the interior offensive linemen in the uniform numbering system.
Players are prohibited from wearing torn or altered equipment. Tear-away jerseys are banned.
During kickoffs, punts, and field goal attempts, players on the receiving team cannot block below the waist.
The zone in which crackback blocks are prohibited is extended from 3 yards on either side of the line of scrimmage to 5.
Players cannot use their helmets to butt, spear, or ram an opponent. Any player who uses the crown or the top of his helmet unnecessarily will be called for unnecessary roughness.
In order to prevent incidents such as the Holy Roller game, the following change is made: If an offensive player fumbles during a fourth down play, or during any down played after the two-minute warning in a half, only the fumbling player can recover and/or advance the ball. This change is known as the "Ken Stabler rule" after the Oakland Raiders quarterback who made the infamous play in the Holy Roller game.1
Referees were outfitted with black identifying hats, while all other officials continued to wear white hats.
For the first time, each official's position was identified on his shirt. The position was abbreviated on the front pocket of the shirt and then spelled out on the back above the number.
The numbering system for officials was altered, with officials numbered separately by position rather than as an entire group, making duplicate numbers among officials common.
Uprights were extended to 30 feet above the crossbar.
Starting in 1978, ten teams qualified for the playoffs: the winners of each of the divisions, and two wild-card teams in each conference.