Whenever the center line of any road constitutes the dividing line between any city or borough and a township located in the same county, the board of county commissioners and the commissioners or supervisors of such township may enter into a contract with the city or borough providing for the grading, curbing and macadamizing or paving of the roadway of said road. The cost thereof shall be borne one-half by the city or borough and one-half by the county and township, in equal portions.
16 P.S. § 5927