(a) Notwithstanding an exemption provided in the federal safety regulations, other than an exemption relating to intracity or commercial zone operations provided in 49 C.F.R. part 395, a rule adopted by the director under this chapter applies uniformly throughout this state.
(b) A rule adopted under this chapter applies to a vehicle that requires a hazardous material placard.

(c) A rule adopted under this chapter may not apply to a vehicle that is operated intrastate and that is:
(1) a machine generally consisting of a mast, engine, draw works, and chassis permanently constructed or assembled to be used and used in oil or water well servicing or drilling;
(2) a mobile crane that is an unladen, self-propelled vehicle constructed as a machine to raise, shift, or lower weight; or
(3) a vehicle transporting seed cotton.