Jim and Lynn Cauley of Pittsburgh enjoy their tailgate spread outside Heinz Field before a football game between the Steelers and Titans in Pittsburgh, Sunday, Sept. 8, 2013. (AP Photo/Gene J. Puskar)

Niners fans tailgate in the Candlestick Park parking lot before a preseason game between the 49ers and Vikings in San Francisco, Sunday, Aug. 25, 2013. (AP Photo/Ben Margot)

Jaguars fan Michele Weyer of Jacksonville, rides her Jaguar Cooler-Scooter outside the stadium before a game against the Chiefs, Sunday, Sept. 8, 2013, in Jacksonville, Fla. (AP Photo/Stephen Morton)

A fan plays a game before the Broncos take on the Ravens, Thursday, Sept. 5, 2013, in Denver. (AP Photo/Brennan Linsley)

Fans tailgate before a preseason game between the Packers and Seahawks Friday, Aug. 23, 2013, in Green Bay, Wis. (AP Photo/Tom Lynn)

49ers fans toss a football while tailgating in the Candlestick Park parking lot before a preseason game between the 49ers and Vikings in San Francisco, Sunday, Aug. 25, 2013. (AP Photo/Ben Margot)

Fans party hard outside the stadium prior to a game between the Broncos and Ravens, Thursday, Sept. 5, 2013, in Denver. (AP Photo/Brennan Linsley)

Fans enjoying themselves while tailgating prior to a game between the Broncos and Ravens, Thursday, Sept. 5, 2013, in Denver. (AP Photo/Brennan Linsley)