Is a 4-wheeler considered a motor vehicle in Texas?

I recently had a case very similiar.  It depends on a few factors.  Texas Penal Code Section 38.04 and 541.201 of the Texas Transportation Code are probably what will apply: however, I would encourage you to see the advice of an Attorney who does criminal law as it can be a felony under certain circumstances for evading arrest for being on a four wheeler and "running from the police" so to speak. Also, do not allow your son to explain, talk, text, email or use social media regarding what did or did not happen! Anything he says can and will be used against him given the right circumstances. Get your son to a lawyer. Hope this helps.