See now, I guess it's all in perspective. To me, I-84 starts in Utah (about 10 miles north of my place) at Echo Junction.
And I always thought US 40 began at Silver Creek junction (about 10 miles south of my place) and headed east to Denver and points beyond, but there are still parts of it in NorCal. I guess I-80 swallowed it up.
The road I live on has a name, but some still call it the Old Lincoln Highway. I guess I-80 ate it up, too, and I further suppose that at some point, Highway 40 and the OLH were the same road from Silver Creek west.
Yeah, old maps are way cool!