Well, this is interesting.  The article you linked to is from 2004. I pulled out a segment here:

"The earlier copy, referring to the solid double-yellow line, stated, "Even if it is not marked "No Passing,' passing by traffic traveling in either direction is not allowed on roads marked in this manner."

The new version said simply, "A double yellow centerline indicates that you should not pass in either direction of travel," and that text remains in the current manual.

Notice the choice of words: "Should not" pass. It doesn't say "must not" pass, or, as in the earlier version, that passing "is not allowed."

The Warrior believes the problem lies in the wording of the state Vehicle Code, Section 3307, "No-passing zones," which states that signs shall be placed marking the beginning and end of each zone. Under compliance, it adds, "Where signs and markings are in place no driver at any time" shall pass. (Emphasis added)."

The Drivers Manual I downloaded says Jan 2015 version (at least that is what I think it says).  Here is what it says:

"As a general rule, broken traffic lines can be crossed and solid yellow lines can not, except when making a turn.

A double, solid yellow centerline shows the center of a two way roadway. Even if it is not marked with a No Passing sign, passing by traffic in either direction is not allowed on roads marked in this manner.

The combination of a solid yellow and broken centerline also shows the center of a two way roadway. You may pass if the broken line is on your side of the road and safe conditions exist, but you may not pass when a solid yellow line is on your side of the road."

It appears to me the language was changed, confusion resulted, and the language was changed back to what it was previously. At least, that is what I see. 

I thought about emailing this question to someone - maybe someone at PennDot - for clarification. However, reading further in that article, I think I already know what response I will get from PennDot - you cannot pass on a solid yellow line.  What impartial person would you suggest sending this question to, for clarification?  

Or maybe accept that the Drivers Manual is correct - you cannot pass on a solid yellow line.

??