Section 312.7 - Balance maintained in fund1. The treasurer of state shall maintain in the road use tax fund in the state treasury, of the funds collected as provided in chapter 321 or as said chapter may be amended, a cash balance sufficient, when added to the cash balance of receipts in the road use tax fund from other sources, to pay the anticipated expenditures from the road use tax fund for the ensuing month.2. When necessary to restore the balance in the road use tax fund in the state treasury, the treasurer of state shall draw upon the treasurer of each county of the state in proportion to the amounts in their possession, respectively, of the funds collected under the provisions of chapter 321 or as said chapter may be amended, and credited to the road use tax fund, a sum sufficient in the aggregate to restore the cash balance in the road use tax fund. Such drafts shall be honored by the treasurer of each county upon presentation.C24, 27, 31, 35, §4772, 5003; C39, §4686.26, 4772, 5010.03; C46, §310.26, 316.17, 321.147; C50, §308A.7; C54, 58, 62, 66, 71, 73, 75, 77, 79, 81, §312.7