40-24-07. Street improvement assessments extended over a period of not more than thirty years

40-24-07. Street improvement assessments extended over a period of not more than thirty years. Special assessments for the expense of opening, widening, grading, graveling, or extending streets shall be payable in equal annual amounts, or in such annual amounts as will permit the annual increase in payment of principal to approximate the annual decrease in the interest on amounts remaining unpaid, extending over a period of not more than thirty years.