Idaho Code § 40-1404
For counties with a population of two hundred thousand (200,000) persons or less, if there is a majority affirmative vote at the election the county commissioners, at their next meeting shall organize the countywide highway district. The county shall be subdivided by the county commissioners into three (3) subdistricts, designated subdistricts number one, two and three, as nearly equal in population as practicable, and one (1) highway commissioner shall represent each subdistrict and be a resident of the subdistrict. The governor shall appoint the first countywide highway district commissioners. Where one (1) or more highway districts have been in existence at the time of the creation of the countywide highway district, the governor shall appoint, whenever practicable, at least one (1) of the former highway district commissioners as they shall qualify by reason of residence in the territorial limits of the subdistricts of the countywide highway district as a commissioner of the countywide highway district. County commissioners and city council members shall not be eligible to hold office as a countywide highway district commissioner. The originally appointed commissioners shall serve until the next general election when two (2) members shall be elected for two (2) years and one (1) member shall be elected for a term of four (4) years, the commissioner from subdistrict number one being elected for a term of four (4) years. The four (4) year term shall be allotted thereafter in rotation to subdistricts number two, three and one. A qualified voter of the countywide highway district shall be eligible to vote for each of the countywide highway district commissioners, and the election shall be conducted as provided by Idaho statutes relating to holding elections at the county level.
The highway commissioners shall take office on January 1 of the year immediately following their election, and each may be compensated in accordance with the provisions of section 40-1314, Idaho Code, or receive a salary not to exceed six hundred dollars ($600) per calendar month with the exception of the president of the highway commissioners who may receive a salary not to exceed seven hundred dollars ($700) per calendar month.
Idaho Code § 40-1404