Complex sentence: Further north I-39 along the runs south and east sides of Rockford, concurrent with U.S.20 until it joins the Jane Addams Memorial Tollway and Interstate 90 near Cherry Valley.
Split into simpler sentences: Further north I-39 runs along the south and east sides of Rockford, concurrent with U.S.20. The interstate joins the Jane Addams Memorial Tollway and Interstate 90 near Cherry Valley.