Here you go. PA Law
Here is the relevant reading:
§ 3305. Limitations on overtaking on the left.
No vehicle shall be driven to the left side of the center or marked center line of the roadway in
overtaking and passing another vehicle proceeding in the same direction unless the left side is clearly
visible and is free of oncoming traffic for a sufficient distance ahead to permit the overtaking and
passing to be completely made without interfering with the operation of any vehicle approaching from
the opposite direction or any vehicle overtaken. In every event the overtaking vehicle must return to
an authorized lane of travel as soon as practicable and, in the event the passing movement involves the
use of a lane authorized for vehicles approaching from the opposite direction, before coming within
200 feet of any approaching vehicle.
Cross References. Section 3305 is referred to in sections 1535, 1603, 3326, 3327 of this title.
§ 3306. Limitations on driving on left side of roadway.
(a) General rule.--No vehicle shall be driven on the left side of the roadway under any of the following conditions:
(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.
(b) Application of section.--This section does not apply under the conditions described in section
3301(a)(2),(3),(4) and (5) (relating to driving on right side of roadway).
Cross References. Section 3306 is referred to in sections 1535, 1603, 3326, 3327, 6506 of this
title.
§ 3307. No-passing zones.
(a) Establishment and marking.--The department and local authorities may determine those
portions of any highway under their respective jurisdictions where overtaking and passing or driving
on the left side of the roadway would be especially hazardous and shall by appropriate signs or
markings on the roadway indicate the beginning and end of such zones and when the signs or
markings are in place and clearly visible to an ordinarily observant person every driver of a vehicle
shall obey the directions of the signs or markings. Signs shall be placed to indicate the beginning and
end of each no-passing zone.
(b) Compliance by drivers.--Where signs and markings are in place to define a no-passing zone
as set forth in subsection (a), no driver shall at any time drive on the left side of the roadway within
the no-passing zone or on the left side of any pavement striping designed to mark a no-passing zone
throughout its length.
(c) Application of section.--This section does not apply under the conditions described in section
3301(a)(2) and (5) (relating to driving on right side of roadway).
At one point someone told me passing on double yellow was legal if the person being passed was going under the posted speed by a certain amount, but that apparently was false information as there need be no provision for speed difference under the guidelines. Just so long as there isn't a sign and it's safe to pass, go ahead, at least in PA.
Amos
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