In the supplemental police report located over at The Smoking Gun, Kurt Busch's girlfriend (that he called his wife during the incident) claimed she was: "drunk and bitching at him and that's why he was speeding and the way he was."
After Kurt consented to taking the brethalizer, he said to the officer "You're only doing this because you're a Jeff Gordon fan."
I'm not making this stuff up...
Oh, he had one Margarita at a Mexican restaurant. I guess it doesn't make you legally drunk - it just makes you an ass.