(a) This chapter does not apply to a government vehicle.
(b) The provisions of this chapter do not apply to an officer, agent, or employee of the United States, this state, or a political subdivision of this state while operating a government vehicle in the course of that person's employment.
(c) The provisions of this chapter, other than Section 601.054, do not apply to a motor vehicle that is subject to Chapter 643.
(d) In this section, "government vehicle" means a motor vehicle owned by the United States, this state, or a political subdivision of this state.