Iowa Code Title VIII. Transportation [Chs. 306-330B] § 311.30. Certificates registered--payment

The county treasurer shall, in connection with the road account for said district, enter the name and post office address of all persons to whom any of said certificates are issued, with a particular designation of the certificates delivered to each person. Any subsequent holder may present the certificate to the county treasurer and cause the subsequent holder's name and post office address to be entered in lieu of that of such former holder. Whenever the fund for such particular district has money to pay the first retirable certificate or certificates, the county treasurer shall, by mail, as shown by the county treasurer's records, promptly notify the holder of such certificate of such fact and that from and after ten days after the mailing of such letter all interest on such certificates will cease.