When this western branch of I-84 was on the drawing board it was designated I-82. But delays and one thing and another ultimately resulted in another route being so named. Thus when the powers that be decided to scuttle the I-80N name they chose I-84, which totally flies in the face of the south to north naming system, for I-82 lies north of I-84.
That's not right.
If you need further explication, look it up.
Yep; I lumber along toward the 85th!