As used in this chapter:

(1) "dBA" means the sound level in decibels measured using the "A" weighting network on a sound level meter as specified in the American National Standard Specification for Sound Level Meters S1.4-1971. A decibel is a unit of sound, based on a logarithmic scale, of the ratio of the magnitude of a particular sound pressure to a standard reference pressure of 20 micropascals;

(2) "Department" means the department of ecology;

(3) "Director" means director of the department of ecology;

(4) "Gross vehicle weight rating (GVWR)" means the value specified by the manufacturer as the loaded weight of a single vehicle;

(5) "In-use" motor vehicle is any motor vehicle which is used on a public highway, except farm vehicles as defined under RCW 46.04.181;

(6) "Motor vehicle" means any vehicle which is self-propelled, used primarily for transporting persons or property upon public highways and required to be licensed under RCW 46.16.010 (aircraft, water craft and vehicles used exclusively on stationary rails or tracks are not motor vehicles as that term is used herein);

(7) "Motorcycle" means any motor vehicle having a saddle for the use of the rider and designed to travel on not more than three wheels in contact with the ground, except farm tractors;

(8) "Muffler" means a device consisting of a series of chambers or other mechanical designs for the purpose of receiving exhaust gas from an internal combustion engine and effective in reducing noise to comply with the standards of this chapter;

(9) "New motor vehicle" means a motor vehicle manufactured after December 31, 1975, whose equitable or legal title has never been transferred to a person who, in good faith, purchases the new motor vehicle for purposes other than resale;

(10) "Off-highway vehicle" means any self-propelled vehicle not used primarily for transporting persons or property upon public highways nor required to be licensed under RCW 46.16.010;

(11) "Person" means any individual, corporation, partnership, association, governmental body, state agency or other entity whatsoever;

(12) "Public highway" means the entire width between the boundary lines of every way publicly maintained by the department of highways or any county or city when any part thereof is generally open to the use of the public for purposes of vehicular travel as a matter of right;

(13) "Sound level" means a weighted sound pressure level measured by use of a sound level meter using the "A" weighting network and reported as dBA.