Driving in Texas
Public nudity is prosecuted under Tex. Pen. Code Ann 42.01(a)(10) A person commits an offense if he intentionally or knowingly . . . exposes his anus or genitals in a public place and is reckless about whether another may be present who will be offended or alarmed by his act. The idea that being in a state of nudity is not an inherently expressive and thus is not subject to First amendment analysis. City of Erie, et al. v. Paps A.M., Tdba "Kandyland", 529 U.S. 277 (2000). Furthermore, a man was convicted in Texas for disorderly conduct while on a public beach in the mist of several 100 other nudist where individuals could see their genitals. Lacour v. State 21 S.W.3d 794 (Tex.App.Beaumont 2000, no pet.).
I would say driving naked would likely appear that you intentionally if not recklessly exposing your genitals to the general public.