Complex sentence: It cannot be signed as an Interstate until it has permanent connections to the east and west, both of which have not been determined due to the King Coal Highway in West Virginia being built as a corridor-standard roadway for US 52.
Split into simpler sentences: It cannot be signed as an Interstate until it has permanent connections to the east and west. The eastern connection has not been determined, in part, because the King Coal Highway in West Virginia is being built as a corridor-standard roadway for US 52.