 When this area of I-15 was completed in 1964, the state legislature realigned SR-1 to coincide with the interstate, so to "maintain continuity" in the state highway system, they redesignated portions of the old SR-1 as extensions of SR-26 (from Santaquin to Spanish Fork), SR-56 (from Spanish Fork to south Springville) and SR-8 (now known as US-89 from south Springville via Provo, Orem, Lindon, Pleasant Grove, and American Fork to the north Lehi interchange).In doing so, the southern terminus of SR-56 was moved south to its current location, which at the time was an intersection with US-6.What was the original portion of the route was now a spur to connect the interstate, while the main alignment now turned east on 800 North to follow the former SR-1 along US-91.