On the day fixed to hear the petition, proof of the notice given being made satisfactory, the county or district highway commissioners shall hear the petition, examine witnesses, and determine whether or not a bridge as petitioned for is necessary. If the petition is approved the county or district highway commissioners shall determine the type of bridge to be constructed, prepare plans and specifications, invite bids, let the contract, have the bridge erected, and provide payment for it.
Idaho Code § 40-1203