(a) General rule.--The costs and expenses of the improvements done under section 12930 (relating to power to grade, pave and macadamize) shall be paid, in whole or in part, by the city or by the owners of real estate bounding and abutting the improvement.
(b) Assessment.--Cost and expense upon the abutting real estate shall be assessed in accordance with Chapter 145A (relating to assessments for public improvements).