NHTSA references several SAE standards in their regulations, but they don’t update the references very often, if ever. Many of the referenced standards date back to versions from the '70s and '80s. Back around 2012 I contacted SAE to find out if they provided a package of standards incorporated by reference in NHTSA regulations. I was told they don’t provide such a package, and they couldn’t even sell me the individual standards I needed because they were “out of date”. My only option through SAE was to buy the latest version.
Shortly afterwards Public.Resource.Org posted the standards, and I copied them. But I thought they had lost their court case.