Michigan Highway 17 is a short remnant route, now relegated to Ypsilanti and the east side of Ann Arbor. Ann Arbor and Ypsilanti are twin cities right next to each other, with Ann Arbor farther west than Ypsilanti. Interstate 94, which flanks both cities to the south, has an alternate business loop that runs through downtown Ann Arbor. That business loop, instead of continuing easterly into Ypsilanti, gets cut off by the US Route 23 freeway that runs north-south between the two cities. The east-west main street through both cities now continues east into Ypsilanti with no business loop designation, since that business loop decided it was too good for Ypsilanti. That's where Michigan Highway 17 picks up the slack; it sort of serves as the east-west business route through downtown Ypsilanti. The western end of Michigan Highway 17 is that interchange I mentioned at US Route 23, where Business Loop 94 turns up its nose at Ypsilanti after serving Ann Arbor. The eastern end of Michigan Highway 17 is a split with US Route 12 on the east side of Ypsilanti.
My photo of Michigan Highway 17 is a westbound reassurance marker for traffic leaving the intersection with Hewitt Road. This intersection is about two miles east of the western terminus of Michigan Highway 17 at US Route 23. Michigan likes to put reassurance markers at a great number of different intersections, even with minor arterials and various crossroads in the country. This photo was taken in March 2019, during a trip around central and south-central Michigan.