(a) General rule.--
(1) Any borough may enter into a written agreement with an adjoining municipality for improving streets, including streets that are boundaries between the borough and the municipality, and may provide in the contract for the division of the damages, costs and expenses of the improvement.
(2) The borough may assess its share of the costs against the owner of property abutting upon the borough's side of the improvement in the manner provided in Chapter 21A (relating to assessments and charges for public improvements) or may agree to pay any part of the costs, damages and expenses of the improvements out of the general funds.
(3) The portion of the damages, costs and expenses agreed to be paid by the borough shall be ascertained as provided in the law governing eminent domain.
(b) Street dividing borough and township.--
(1) If the center line of any street constitutes the dividing line between a borough and a township located in the same county, any agreement to improve and maintain the street shall be made with the governing bodies of the township and, if necessary, the county.
(2) The improvement shall be constructed and subsequent repairs shall be made under the supervision of the borough and in compliance with plans to be agreed upon, in writing, by the parties.
(3) One-half of the cost of the repairs shall be borne by the borough. The borough may assess its share of costs against the owners of real property abutting on the borough's side of the improvement in the manner provided in Chapter 21A.
(c) Street dividing borough and any other municipality.--
(1) If any street, more than one-half the width or the entire width of which is within the limits of any borough, divides the borough from any other municipality, the street may be improved by the borough.
(2) The property abutting on the side of the street which is located outside the limits of the borough making the improvements may, for a depth of 150 feet, plus one-half the width of the street, from its center line, be assessed for any and all municipal improvements to or on the street in accordance with Chapter 21A.
(d) Street outside limits of borough.--A borough may appropriate and expend money for the improvement of a street, not to exceed one mile in length, outside the limits of the borough for the purpose of connecting improved streets in the borough with State highways, interstate highways and county roads.