The Michigan State Highway Department (MSHD) completed the freeway bypass of the Ann Arbor–Ypsilanti in 1956, then moved the M-17 designation back to Washtenaw Avenue, Michigan Avenue and Ecorse Road, removing Bus. M-17 in the process. US 12 and US 112 replaced the BYP US 112 designation on the freeway. The former US 112 designation through downtown Ypsilanti was converted to a BUS US 112 designation, including sections concurrent with M-17. Another change was made to the Ann-Arbor section of the highway as it was truncated to end at US 23. The 1962 completion of the US 23 freeway through the Ann Arbor area by MSHD moved the western terminus of M-17 west to meet the new freeway at the current terminus. The eastern terminus was progressively scaled back starting in 1968. The US 25 concurrency was removed and the terminus was moved to M-39/Southfield Road in Allen Park. A second truncation scaled the terminus back to US 12, the current eastern endpoint.