Actually, saying you are NOT a "legal person" is a valid rebuttal, provided you do it correctly. Consider the following:
A "driver" or "operator" is a LEGAL person, which is not at all the same as a NATURAL person in law. In many statutes, person is defined by default to encompass ONLY that which constitutes a LEGAL FICTION.

Case in point, Sec. 311.005 of the Texas Government Code:

Sec. 311.005. GENERAL DEFINITIONS. The following definitions apply unless the statute or context in which the word or phrase is used requires a different definition:
...
(2) "Person" includes corporation, organization, government or governmental subdivision or agency, business trust, estate, trust, partnership, association, and any other legal entity.

This is the DEFAULT definition in EVERY statute for the term "person" in statute UNLESS the statute contains its own LOCAL definition of person. Notice that by default the term encompasses ONLY those things that are creations of law, i.e. LEGAL ENTITIES, not natural persons.

Then we turn to the 2008 Texas Legislative Drafting Manual, which contains two very telling sections on the subject of "person." This is subsection (d) on page 12 of the Manual in pertinent part:

(d) Artificial definitions. A word should never be given a strained or artificial meaning out of keeping with its ordinary usage. (An exception to this rule is “person.” See Subsection (h).)

Now, this is subsection (h) in that same Manual:

(h) “Person.” It is often desirable to define “person” broadly, such as “an individual, corporation, or association.”1 Although this violates the rule against giving a word an artificial meaning, the advantage of avoiding unnecessary repetition and the long-standing practice of so defining this word outweigh the policy behind the rule. Section 1.07 of the Penal Code defines “person” in this way and, as already noted, Penal Code definitions also apply to penal laws outside the code. While it is legally unnecessary to redefine “person” in a penal law outside the code (except to provide a different definition), the express adoption of that definition (see the following subsection) may be helpful to alert users of the statutes who may be unaware of the general application of Penal Code definitions. The definition of “person” in Section 311.005, Government Code, applies to those codes to which the Code Construction Act applies and that do not otherwise define the term.

Notice also how subsection (i) suggests that definitions be propagated so as to avoid any 'confusion' about which one applies where several possibilities exist:

(i) Adoption of definition by reference. When it is desired that a term have the same meaning when used in separate but related laws, it may be useful to include a definition in the second law that adopts by reference the definition in the first law. For example:

Sec. 21.151. DEFINITION. In this subchapter, “teacher” has the meaning assigned by Section 21.101.

What is of note on this subject is the intentionally misleading discussion in subsection (h) about using Penal Code definitions in punitive statutes outside of the Penal Code. Sec. 311.005 does not make any such statement or exception in its language, so why does the drafting manual try to put words into the law that is not there? However, they DID leave a catch- all, and that is the applicability of the Code Construction Act itself, which shoots that misleading statement right between the eyes.

Here is the entire category of codes and statutes that Sec. 311.002 of the Code Construction Act says that Act applies to, which is ALL of them:

Sec. 311.002. APPLICATION. This chapter applies to:

(1) each code enacted by the 60th or a subsequent legislature as part of the state's continuing statutory revision program;

(2) each amendment, repeal, revision, and reenactment of a code or code provision by the 60th or a subsequent legislature;

(3) each repeal of a statute by a code; and

(4) each rule adopted under a code.

Acts 1985, 69th Leg., ch. 479, Sec. 1, eff. Sept. 1, 1985.

I do not see one word regarding legislatively authorized exceptions for Penal Code definitions to be used in place of those provided by the Code Construction Act, nor is the Penal Code ever mentioned as being an exception alongside the "local definition" rule that exempts the local statute's definition from being the same as the defaults contained in Sec. 311.005 of the Act.

Also, take note of the last sentence in subsection (h) that reads:

"The definition of “person” in Section 311.005, Government Code, applies to those codes to which the Code Construction Act applies and that do not otherwise define the term."

Why is that sentence so important? Because THIS is what Sec. 1.002 of the Texas Transportation Code says in relation thereto:

"Sec. 1.002. CONSTRUCTION OF CODE. Chapter 311, Government Code (Code Construction Act), applies to the construction of each provision in this code except as otherwise expressly provided by this code.

Acts 1995, 74th Leg., ch. 165, Sec. 1, eff. Sept. 1, 1995."

Now, guess what virtually every other code other than the Penal Code has at its beginning regarding the Code Construction Act? Yep, this very same proviso regarding statutory terms and construction.

Therefore, the ONLY valid conclusion about interpreting the 'penal' provisions of the Texas Transportation Code using the Penal Code definition of "person" rather than the definition contained in Section 311.005, is that this interpretation is DEAD FUCKING WRONG, and you see it right here in black letter law that that is precisely what it is. Nowhere does the Texas Transportation Code contain ANY provision stating that "the term "person" shall have the same meaning as assigned by Section 1.07(a)(38) of the Penal Code." But it DOES have this provision saying that the definition in Section 311.005(2) absolutely DOES apply and is to be used in every place where the local statute does not redefine it.

Hence, the only logical conclusion to be made about the actions of the judges who preside over these kinds of cases and those who hear the appeals therefrom falls into one of three categories, or some combination thereof:

1) criminally negligent;
2) criminally incompetent; and/or
3) criminally corrupt.

Why? Because these Fidiots with delusions of grandeur and self-importance don't WANT to know what the law actually is so they can claim ignorance, intentionally avoid knowing the law so they can claim ignorance, or either know the law or refuse to become knowledgeable of it so they can simply steal money for their employer and themselves via their paycheck. In any case, such people shouldn't be allowed to remain in such positions, and most certainly should be individually

subjected to the same forms of punishment they hand down to us with such fervent relish from their little thrones for similar offenses.

So, if one addresses the issue thusly, " I was never acting in any legal capacity associated with that of the legal person defined as "driver," or "operator" of a "motor vehicle," then you are actually stating a salient affirmative legal defense, because they are only PRESUMING such facts, not actually presenting any substantive evidence in support of them 99% of the time.