Well, it would appear there isn't, but here is Chris' answer in full.
If there is a "Highway Code" over here I've never seen it in operation. If you are talking about the US equivalent of the Highway Code book then I don't ever remember seeing a copy of it. As for manners on the Highway ("Highway Code"), the Americans don't have manners because each American assumes that he is the safest driver on the road and of course the attitude behind the wheel is, "I'm No.1, I'm always first and screw everyone else on the road." That is why it is always the other driver's fault in an accident. Overtaking on the inside, tailgating and veering across all five lanes of a freeway right at the last moment for "my exit" in front of everyone else on the road is a way of life here. Some states have reputations for bad driving more than others. My own personal feeling is that here in Arizona the sun is the biggest enemy. Makes for some interesting gestures from right hands waving behind the driver of the car in front of you. Then of course you have to watch out for the highway code of being shot at if the deranged person driving in your immediate vicinity has a gun. Is that what you meant by the Highway Code ?