Pennsylvania Statutes Title 75 Pa.C.S.A. Vehicles § 3306. Limitations on driving on left side of roadway

(1) When approaching or upon the crest of a grade or a curve in the highway where the driver's view is obstructed within such distance as to create a hazard in the event another vehicle might approach from the opposite direction.

(2) When approaching within 100 feet of or traversing any intersection or railroad grade crossing, unless otherwise indicated by official traffic-control devices.

(3) When the view is obstructed upon approaching within 100 feet of any bridge, viaduct or tunnel.