T.F.
I have a cousin who lives half the time in England and half the time here. Her husband is from England and his business brings them here often. It has been 8 years and 4 children later...she drives in England with her US license and he drives here with his license from England.
I know he is a speed demon and has been stopped a lot and it has never been an issue. If anything, he got special treatment!!
My husband travels to Mexico and Canada and I rent cars for him. He shows his passport and TXDL. No issues. However, he is on the road weekly and we spend about $1000 a month on rental cars so when his name is pulled up within the system of Hertz or Alamo, he is recognized as a routine renter.
With all that said.....I do not know the specific "rules".