"The theory that Colorado drivers are some of the worst in the nation now has data to back it up."

I disagree.  In my experience, New York, Massachusetts, and Quebec drivers are among the very worst.  Colorado drivers are more polite than those on the coasts — more likely to yield and let you into their lane, for example.  But no more polite than those in the Midwest or South.

The greatest sin of Colorado drivers is the sin of pride.  The think they are better on the snow or ice than newcomers but, thanks to that familiarity, they actually are merely pushing the envelope and inviting an accident.  I'm sure the State Patrol would agree that Colorado drivers don't modify their behavior to match deteriorated conditions nearly enough.  That are NOT bulletproof.