I haven't read any of the comments posted yet but in California they set a certain amount of money aside in the budget for this kind of thing.
Get the mile marker number, what lane number it was, date and time of incident, conditions, speed and it wouldn't hurt to get pictures of the hole itself.
Get all receipts of the amount of the repair, parts etc and get a claim form from the state that you're in. It takes some time but it's worth it when you finally get your check.
Get an alignment of course an you want to do it right. Ultimately they just hope you go away and don't do anything but when you have all the evidence on your side it's hard to dispute. Tell them you even have a witness if necessary.