Counsel for XX argued that I.C. 49-902, 49-903 and 49-905 do not require headlights to be in working condition before sunset. The magistrate agreed, explaining that XX' vehicle was properly equipped with headlights, only that one was not working or illuminated prior to the stop at 7:20 p.m., which was prior to sunset and therefore not a violation of the Idaho Code. Thus, the magistrate granted XX' motion to suppress evidence in the DUI case for lack of reasonable suspicion of wrongdoing to justify the stop of XX' vehicle. The state appealed to the district court. the district court reversed the magistrate's decision, ruling that Johnson had probable cause to stop XX because it is unlawful to drive with only one operable headlight. XX appeals. We affirm. The instant case involves the meaning of and interaction among several statutes: I.C. 49-902(1), 49-903 and 49-905. We exercise free review in questions of statutory construction. State v. Nunes, 131 Idaho 408, 409, 958 P.2d 34, 35 (Ct. App. 1998) (citing State v. O'Neill, 118 Idaho 244, 245, 796 P.2d 121, 122 (1990)). In construing these statutes, we must attempt to give effect to the intent of the legislature. Nunes, 131 Idaho at 409, 958 P.2d at 35. Legislative intent is determined by the plain language of the statute. Id. When a statute is clear and unambiguous, it must be interpreted in accordance with its language, courts must follow it as enacted, and a reviewing court may not apply rules of construction. State v. Dewbre, 133 Idaho 663, 665-66, 991 P.2d 388, 390-91 (Ct. App. 1999); State v. Schumacher, 131 Idaho 484, 485, 959 P.2d 465, 466 (Ct. App. 1998). Idaho Code 49-902(1) and 49-905 describe the condition of equipment that must be on a vehicle under Idaho law. Idaho Code 49-902 states in pertinent part that: (1) It shall be unlawful for any person to drive, or move, or for the owner to cause or knowingly permit to be driven or moved on any highway any vehicle or combination of vehicles which is in an unsafe condition as to endanger any person, or which does not contain those parts or is not at all times equipped with the lamps and other requirements in proper condition and adjustment, as required by the provisions of this chapter, or which is equipped in any manner in violation of the provisions of this chapter. The plain language of this act requires that the "lamps and other requirements" be "at all times . . . in proper condition and adjustment." However, XX argues that the succeeding clause, "as required by the provisions of this chapter" is a limitation on the preceding clause requiring that vehicles be "at all times equipped with the lamps and other requirements in proper condition and adjustment." He argues that I.C. 49-903 is the section setting forth the time when headlights must be operable. Idaho Code 49-903 provides as follows: Every vehicle upon a highway at any time from sunset to sunrise and at any other time when there is not sufficient light to render clearly discernible persons and vehicles on the highway at a distance of five hundred (500) feet ahead shall display lighted lamps and illuminating devices as here respectively required for different classes of vehicles, subject to exceptions with respect to parked vehicles as stated herein. By its plain language, this section only states when headlights must be turned on. This statute does not authorize the operation of vehicles with inoperable headlights on Idaho highways. For numerous reasons, operable headlights may be unexpectedly required long before sunset: sudden changes of weather; agricultural dust; smoke from burning fields or forest fires to name a few. We therefore conclude that XX' reading of I.C. 49-903 as permitting the operation of vehicles with inoperable headlights before sunset is inconsistent with Idaho's policy of providing a safe highway system. The statutes making up Chapter 9 of Title 49 concern the same subject matter-the specific type and condition of equipment on motor vehicles. These statutes refer to one another and must be read in light of these references. In construing the meaning of these statutes, we are mindful of the principal rule governing statutory interpretation. "Statutes must be interpreted to mean what the legislature intended for the statute to mean." State v. Paul, 118 Idaho 717, 718-19, 800 P.2d 113, 114-15 (Ct. App. 1990). Statutes which are in pari material-of the same subject matter-are to be construed together, so as to further the legislative intent. Id. Idaho Code 49-905 provides: (1) Every motor vehicle other than a motorcycle or motor-driven cycle shall be equipped with at least two (2) head lamps with at least one (1) on each side of the front of the motor vehicle. the head lamps shall comply with the requirements and limitations set forth in this chapter. (7) Any person convicted of a violation of the provisions of this section shall be guilty of an infraction. This section plainly refers back to other sections setting forth more specific requirements for head lamps. Looking at these more specific sections, we note, again, that Idaho Code 49-903 only governs when headlights must be turned on. Idaho Code 49-902(1) specifies the condition of the equipment, including head lamps. the plain meaning of "in proper condition and adjustment" is in proper working order. Accordingly, when Johnson saw that one of the Firebird's headlights was on while the other was not, he had reasonable cause to believe XX was operating a vehicle in violation of Idaho Code 49-902(1), which is an infraction pursuant to Idaho Code 49-905.