67 Pa. Code § 212.6 – Removal of traffic hazards.

(a) Interfering signs, lights or markings. The Secretary and local authorities, under their respective jurisdictions, have the authority to cause the removal of all colored or flashing lighted signs or other lights, signs or markings so located as to interfere with traffic or to be confused with or to obstruct the view or effectiveness of traffic-control devices.
(b) Trees, plants, shrubs or other obstructions. The Department on State-designated highways, and local authorities on any highway within their boundaries, may require a property owner to remove or trim a tree, plant, shrub or other obstruction or part thereof which constitutes a traffic hazard. The following are examples of traffic hazards:
1. (1) The obstruction restricts the stopping sight distance for drivers of through vehicles or the available corner sight distance for drivers entering from side roads or driveways to distances less than the appropriate minimum stopping sight distance or minimum corner sight distance values.
2. (2) The obstruction critically restricts the sight distance to a traffic-control device.
3. (3) Vehicle crash records indicate that a crash has involved the obstruction or that the obstruction contributed to one or more of the vehicle crashes.