What’s interesting about that “map” is you can clearly see the routing of Interstate route 5, 80, 15 and 84 across the western states. And you can see the “split” of Interstate 5 and California 99 between Sacramento, CA and the merge between I-5/CA 99 just north of Wheeler Ridge, CA.
Interesting. You must be in Northern California. As a Southern Californian who drives up the Central Valley a couple times a year, I would say I-5/99 splits near Wheeler Ridge and merges near Sacramento.