Doing some homework on the issue. This from the PennDOT site:
Q. Why does PennDOT not replace curbs and sidewalks?
A. By Pennsylvania State law, the local municipality or property owner is responsible for the maintenance or installation of curbing and sidewalk [emphasis mine]. Furthermore, it is District 8-0 policy to use betterment funds for roadway improvements and not curbing and sidewalk. However, in certain unusual circumstances, the Department has replaced curbing and sidewalks. In an effort to minimize the need for right-of-way acquisition, curbing has been installed. Also, in areas where reconstruction, widening or substantial roadway grade changes result in removal of existing curbing and sidewalk, the Department may consider replacement in kind.