As used in this chapter and chapters 1 and 2 of this title, unless the context otherwise requires:
(1) “Commissioner” means the commissioner of transportation;
(2) “Department” means the department of transportation; and
(3) “Road” or “highway” is construed to include all bridges upon or that form a part of the highway to be constructed, reconstructed or maintained under this chapter and chapters 1 and 2 of this title.