A small section of the B2B trail, east of Ypsilanti, uses streets. Also the route from Dexter to Chelsea, and Chelsea toward Lyndon/Stockbridge, uses roads.
You'll use bike lanes in some locations, such as along Huron River Drive between Ann Arbor and Dexter.
The rest of the trail is off-road, although you will need to cross streets in a few places.
Photo: Trevor ScottHuron River Drive northwest of Ann Arbor