Source: December 31, 2016 Interstate Route Log and Finders List
Interstate 375 shown as an extension of Interstate 75 leading to Downtown Detroit in 1961.
U.S. 10, 12, 16 and 112 all ended in Downtown Detroit at one time, while U.S. 25 ran through the central business district along Fort Street and Gratiot Avenue. Only U.S. 12 remains in Downtown Detroit today, having been realigned to overtake U.S. 112 in 1961.
The Chrysler Freeway opened in 1963 as an extension of I-75 to Downtown.
Completion of the Fisher Freeway (I-75) west from Gratiot Avenue (M-3 / old U.S. 25) overtook Vernor Highway to the north of Downtown. Note also that the Lodge Freeway was designated Business Spur I-696 until 1970, when it became a part of U.S. 10.
Interstate 375 comprises a short freeway spur leading southeast from Interstate 75 to the GM Renaissance Center along the Detroit Riverfront at Downtown Detroit. The six-lane freeway travels below grade between service streets through to Jefferson Avenue, where it turns west and transitions into a surface boulevard. 0.167 miles of Jefferson Boulevard west tom the freeway end at Beabien Street and Randolph Street by the Renaissance Center doubles as unsigned Business Spur I-375.
Showing signs of age, studies were underway on how to address future transportation needs for Detroit when it came to Interstate 375. Six options for I-375 were outlined in 2014, ranging from rebuilding the freeway as a below grade expressway or converting it to a surface boulevard. Costs estimates ranged from $45 million to $80 million for design and construction on the various options. A lack of consensus among city leaders, planning agencies and major property owners by January 2016 led to the indefinite delay on any recommendation of the aforementioned options. Instead MDOT will continue repairing overpasses and maintaining I-375 as it is.1
Interstate 375 was constructed at a cost of $50 million and opened to traffic in 1964.1 Interstate 75 defaulted from the Chrysler Freeway south onto Interstate 375 between November 25, 1964 and 1968. Opening at that time was the Fisher Freeway west from Gratiot Avenue (then U.S. 25) and I-375 to 12th Street.2
When U.S. 10 was truncated from Detroit northwest to Bay City in 1986, it was redesignated as M-10 along the John C. Lodge Freeway north from Interstate 75 and Business Spur I-375 south from I-75 (Fisher Freeway) to Jefferson Avenue at Downtown Detroit. Sign changes were slow to follow however, and the business spur portion of old U.S. 10 ended up signed as part of the Trunkline Highway instead.3
Southern Terminus - Business Spur I-375/Jefferson Avenue - Detroit, Michigan
Perspective from Interstate 375/Chrysler Freeway south
Southbound Interstate 375 ends after its interchange with Jefferson Avenue. The route ahead is considered Business Spur I-375/Jefferson Avenue until it turns west to meet the southern terminus of M-10. Business Spur I-375 runs from the Detroit-Windsor Tunnel east to the southern end of Interstate 375. The MDOT Physical Reference Atlas lists the section of Jefferson Avenue between M-3/Randolph Street and the beginning of the Interstate 375 freeway as BS-375/Jefferson Avenue. (Thanks to Chris Bessert for this information.) Photo by John Harmon (2002).
Perspective from Business Spur I-375/Jefferson Avenue east
This sign bridge is located on eastbound Jefferson Avenue, which carries an unsigned designation of Business Spur 375 from U.S. 12 to this locale. Interstate 375 begins to the left as Jefferson Avenue continues to the northeast. Photo by Dan Garnell (09/13/02).
Perspective from Interstate 375/Chrysler Freeway north
We begin on northbound Interstate 375 as it approaches its junction with Interstate 75 one-half mile away ahead. Photo by Frank Gillon (09/03/07).
This overhead sign advises motorists leaving downtown Detroit to use Interstate 75/Fisher Freeway south to Michigan 10/Lodge Freeway, Michigan 3/Gratiot Avenue, and Interstate 96/Jeffries Freeway west to Lansing. Photo by Frank Gillon (09/03/07).
The are right two lanes connect to Interstate 75 south and Michigan 3/Gratiot Avenue at the north end of Interstate 375. The ramp to Michigan 3 is combined with the ramp to Interstate 75 south. Photo by Frank Gillon (09/03/07).
The left lanes of Interstate 375 north will connect to Interstate 75/Chrysler Freeway north to Flint, Interstate 94/Ford Freeway, and Interstate 696/Reuther Freeway. The right two lanes connect to a ramp to Interstate 75 south and Michigan 3/Gratiot Avenue. There is no Interstate 375 ends shield. Note that these signs reflect the fact that Michigan DOT is eliminating the names of the freeways (such as Fisher, Ford, Chrysler, Lodge and Jefferies - see next photobox). Photo by Frank Gillon (09/03/07).
Taken in 2002, this photo shows the freeway names and numerical designations at the same location as the previous photo; these signs are not common now. The northbound conclusion of Interstate 375 occurs at Interstate 75 just east of Comerica Park (home of the MLB Detroit Tigers) and Ford Field (the 2002 new home of the Detroit Lions NFL franchise). The Interstate 75/Fisher Freeway southbound ramp also takes traffic to a connector between Interstate 75 and Michigan 3/Gratiot Avenue. Photo by Dan Garnell (09/13/02).
The split of Interstate 375 north onto Interstate 75 south and Michigan 3/Gratiot Avenue contains a sharp couple of curves. Photo by Frank Gillon (09/03/07).
While on the transition ramp from Interstate 375 north to Interstate 75 south, Ford Field (home of the National Football League Detroit Lions) and Comerica Park (home of Major League Baseball Detroit Tigers) come into view. Photo by Frank Gillon (09/03/07).
Perspective from Interstate 75/Chrysler Freeway south
A diagrammatic sign shows the lane allocation for southbound Interstate 75 approaching Interstate 375 in Detroit, one mile to the north near the Mack Avenue off-ramp (Exit 52). Interstate 75 takes the first of three turns in Detroit at Interstate 375, turning from the southeast to the southwest. At the eastern terminus of Interstate 96, Interstate 75 again turns to the southeast. Photos taken by Frank Gillon (09/03/07) and Dan Garnell (07/02).
To Canada, motorists have two choices from southbound Interstate 75/Chrysler Freeway. The first is to follow Interstate 375 south travels south into downtown Detroit, then connect to Canada via the toll Windsor Tunnel under the Detroit River (oddly enough, Canada is south of the United States due to the geography of the Detroit River and the Great Lakes). The second option is to take Interstate 75 south to the Ambassador Bridge exit, which connects directly to Ontario Provincial Route 3. Photo by Frank Gillon (09/03/07).
Southbound Interstate 75 reaches Exit 52, Mack Avenue. The overhead sign provides lane allocations for the pending split between Interstate 75 south and Interstate 375 south. Note the new Clearview signs to let motorists know that the right two lanes for Interstate 75/Chrysler Freeway and left three lanes for Interstate 375 to downtown is one-half mile ahead. Photo by Frank Gillon (09/03/07).
Interstate 75 prepares to turn westward as Interstate 375/Exit 51C - shown as Exit 51B in the previous photograph) departs towards downtown and the Windsor, Ontario Tunnel. This signage is posted one-fourth of a mile before the split. Auxiliary signage to the right indicates that the right-hand lane also is allocated for Interstate 75 south. Use the left lane to Madison Avenue as the Interstate 375 and Interstate 75 split is ahead. Photos taken by Frank Gillon (09/03/07) and Dan Garnell (07/02).
The right two lanes carry Interstate 75 south from the Chrysler Freeway onto the Fisher Freeway with a 30 mile per hour ramp. This is certainly substandard for a through freeway (it is comparable to Dead Man's Curve on Interstate 90 in Cleveland). The left three lanes continue south onto Interstate 375 into downtown Detroit. Photo by Frank Gillon (09/03/07).
Perspective from Michigan 3/Gratiot Avenue south
This ramp connects Michigan 3 south onto Interstate 375 north. Photo by Frank Gillon (09/03/07).
A second sign for the connection to Interstate 375 is posted shortly thereafter - now we're on the Fisher Freeway Connector westbound. Photo by Frank Gillon (09/03/07).
Perspective the Fisher Freeway Connector west
Once on the ramp, it immediately gains freeway characteristics: This is the stub of the Fisher Freeway. From here, the stub travels due west into the Interstate 75 and Interstate 375 interchange. Stay left to connect to Interstate 75 south to Toledo. Photo by Frank Gillon (09/03/07).
The right two lanes exit onto Interstate 75 north to Flint and Interstate 375 south to downtown Detroit. The next exit on southbound Interstate 75/Fisher Freeway is Exit 50, Grand River Avenue. Photo by Frank Gillon (09/03/07).
A set of trailblazer shields for Interstate 75 north, Interstate 75 south, and Interstate 375 is located at the gore point. Photo by Frank Gillon (09/03/07).
Once on the transition ramp, the left lane connects to Interstate 375 south and the right lane connects to Interstate 75 north. Photo by Frank Gillon (09/03/07).
A gore sign at this location shows the same information as the overhead shown in the previous photo. Photo by Frank Gillon (09/03/07).
"Decision on I-375 delayed indefinitely." Detroit Free Press, January 25, 2016.