sentences:  However, many of the same issues that are being addressed in SIU 5 arise in SIU 6 as well, and the Commonwealth of Kentucky is upgrading the Purchase Parkway in a similar fashion.The massive interchange with US 45 and US 51 at the Tennessee state line in South Fulton is the main challenge for completing SIU 6, and has been broken out as a separate project from SIUs 6 and 7.Kentucky is the only state that will be routing nearly its entire portion of I-69 over existing freeways, allowing the state to avoid years of costly environmental studies, and thereby enabling the KYTC to upgrade the parkways to I-69 as soon as funding becomes available.