Whenever, by majority vote of the legislative authorities of a city mentioned in ORS 373.210 or by initiative vote by the people thereof, it is deemed advisable to construct or improve such designated roads or streets at the partial expense of the general fund of the municipality, the governing body shall so declare by ordinance, stating what portion of the cost shall be paid out of the general fund of the municipality and what portion shall be paid by assessment against property in the manner provided by charter or ordinance provisions of the city, unless the amount or proportion has been fixed by the initiative measure.
Oregon Legal Code