One would be much better served looking on the state of interest's actual website - get the information straight from the horse's mouth.
For instance, in Texas, one can click
HERE, then Texas Statutes, then Texas Transportation Code, Section 521 (non-Commerical) and have at it!!
Editorial aside: Based on my experience, I don't believe 95% of the Texas DPS License and Weights personnel have ever read it.
Rusty