16 Pa. Stat. § 2720
The county commissioners may, in the manner provided by this subdivision (a) 2, cause to be laid out, surveyed and adopted a system of main thoroughfares which said board shall adjudge the proper roads to be established and specially constructed and improved. In adopting such system, the commissioners shall consider the population and needs of all parts of the county and make an equitable distribution of the roads to be specially constructed, located and improved by the said county. They shall cause a plan or plans to be made showing the system of proposed roads, the relation of the proposed roads to existing public roads which connect therewith or are to be supplied thereby, the names of abutting property owners, and also roads which already have been improved by the county. Upon approval of the plan or plans by the commissioners, they shall cause the approval to be engrossed upon the plans and certified by at least two commissioners. The plans shall be filed for public inspection in the office of the commissioners and recorded in the office of the recorder of deeds in a book to be provided for the purpose.
No part of the proposed roads of said system shall be an easement upon private property or in any manner interfere with the use thereof until established as a public road by the action of the court of quarter sessions.
16 P.S. § 2720