I-70 should really swap with I-270 east of Frederick, since Washington is the more important destination
Initially, both DC and Baltimore got a suffix of I-70 (I-70N for Baltimore and I-70S for DC). Imo one of the suffixed splits that actually make sense, as they're in the same urban area and both major cities. Eventually, the suffixes had to be dropped because I-70 isn't I-35, and Baltimore got mainline I-70 as they were still planning their section to I-95 then while DC's was canceled already.