Tailgate parties - beer and barbecue sessions in the car parks near stadiums - are a fact of life in American sport. Why haven't they caught on in the UK, writes Tammy Thueringer."Tailgating" goes right back to the birth of college American football. Then people would gather round wagons. Now it's typically 4x4 cars with their tailgates down.
Fans cram barbecue grills, tents and even televisions into their cars, decorated with team colours, and head to the stadium car park to eat, drink and play games, often for several hours before a game begins.
Briton Adam Goldstein, author of Tailgate to Heaven, has tailgated at every NFL stadium in the US. On his first encounter with tailgating in 2006, he was flabbergasted at the way rival fans mixed peaceably together at the parties. A Chicago Bears fan, he was warmly welcomed into a group of Arizona Cardinals fans and fed. "I was shocked and slightly worried. I thought they were going to poison me. It was just so odd."
That happy mixing of rival fans is one reason why it might be hard to imagine the tradition translating to the UK. It's somehow hard to imagine Manchester United and Liverpool fans cooking each other burgers in a car park. "Because of hooliganism, they [the authorities] don't want our fans integrated before or during the game," Goldstein says.
Then there's some more mundane obstacles. The weather, for one. Although it must be said Americans continue to tailgate in bad weather. But space is a factor.
"In America, most stadiums are surrounded by large car parks," Goldstein says. "But in the UK, stadiums are mainly in residential parts of the city, surrounded by homes so there is little in the way of parking."
And the prevalence of SUVs in the US also helps.
Goldstein also says the US has a more neighbourly and welcoming culture, which is what tailgating is all about.
And British football has the sacred ritual of the pub. Mark Perryman, a research fellow in Sports and Leisure Culture at the University of Brighton, notes that many fans religiously attend the same pubs and do not leave until just before kick-off. "It would be tough to change that and get them out of the pubs more than five minutes before a game."
He also says because football is such a big part of the UK's identity that fans are resistant to changes coming from the outside.
Rugby on the other hand seems to have come closest to adopting tailgating. Twickenham is the scene of what have been described as "Range Rover picnics".