I-75B in Bay City Michigan?

[Roadgeekteen]

I see a road called I-75B in Bay City on google maps. But it's not on wikipedia and does not appear to be signed. What is it?

[Terry Shea]

BS I-75
http://www.michiganhighways.org/listings/MichHwysBus32-94.html

[Flint1979]

It's an I-75 business spur and M-25.

[Henry]

Additionally, it was actually BL 75 until 1971, when a majority of the original route was eliminated. BS 75 is signed along MI 25, but is not shown on any of I-75's exit signs.

1961 (Jan 3) - The segment of I-75/US-10/US-23 and US-23 freeway from Saginaw northerly past Bay City to Kawkawlin is assumed into the state trunkline system and likely opens at this same time. The US-23 designation is moved to this new freeway and several other route designation changes also take place in the Bay City area. While M-13 is extended northerly from Saginaw to take the former route of US-23 through Bay City to Kawkawlin, M-47 north of Saginaw is removed from its Bay City alignment and moved to one running via Freeland toward Midland. Thus, from Exit 160 on the new freeway southwest of Bay City, a new BL I-75 designation replaces M-47 northeasterly into Bay City. (M-84 is assigned to the former M-47 from I-75/US-10/US-23 southerly into Saginaw.) BL I-75 then leaves the former route of M-47 (which continues northerly along Euclid Ave, now designated M-13) and heads easterly co-signed with M-13 via Salzburg Ave, the Lafayette Bridge and Kosciuszko Ave along what was previously US-23 to Garfield Ave. Here, BL I-75 replaces the former BUS US-23 via Garfield Ave, Columbus Ave and Washington Ave into downtown. The new BL I-75 continues westerly, still supplanting BUS US-23 but now co-signed with M-15/M-25 via 7th St (wbd) and McKinley St (ebd), the Veterans Memorial Bridge, and Jenny St (wbd) and Thomas St (wbd) to Euclid Ave (formerly US-23/M-47, now M-13) where M-15 formerly terminated. BL I-75 continues westerly with M-15/M-25 via Jenny & Thomas Sts and the freeway connector to jct I-75/US-23 and US-10 west of Bay City, where BL I-75, M-15 and M-25 all terminate at present-day Exit 162.
   1970 - The concurrent M-15 designation along BL I-75/M-25 from downtown Bay City westerly to I-75/US-10/US-23 is removed from the route.
   1971 - BL I-75 loses more than half of its length when the highway is truncated in downtown Bay City, converting the Business Loop into a Business Spur, designated BS I-75. The portion of the former BL I-75 from I-75/US-10/US-23 at Exit 160 southwest of the city northeasterly via Saginaw Rd, Salzburg Ave, Lafayette Bridge, Kosciuszko Ave, Garfield Ave, and Washington Ave is redesignated as a northerly extension of M-84. BS I-75 now terminates at cnr of McKinley St & Washington Ave (ebd) and 7th St & Washington Ave (wbd), while still running concurrently with M-25 for its entire length between there and its western terminus.

[Flint1979]

These business loops and business Spurs aren't all that important anyway. The highway where you see I-75B is M-25. Exit 162 on I-75 has M-25 with a control city of DOWNTOWN Bay City and US-10 and the control city is Midland