The county board, in a county having a population of less than eighteen thousand inhabitants and less than five commissioners, shall appoint and fix the salary of a county highway superintendent whenever a petition for such appointment is signed by ten percent of the legal voters in the county voting for Governor at the last general election and is filed with the county clerk. If a petition protesting such appointment is signed by ten percent of the legal voters in the county and is filed with the county clerk within ninety days from the filing date of the petition for appointment, the county board shall submit the question to the electors. Within ten days from the filing of the petition for appointment, the county board shall publish notice that such petition has been filed, and such notice shall be published once a week for three consecutive weeks in a legal newspaper published in the county or, if none is published in the county, in a legal newspaper of general circulation in the county. If no petition in protest is filed or if a majority of the votes cast are in favor of appointing a county highway superintendent, the county board shall appoint and fix the salary of such superintendent within six months from the filing of the petition for appointment or from the date of balloting as the case may be.