Michigan Highways: Since 1997.

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Introduction

The 9,669-mile state trunkline system in Michigan is laid-out, designed, and marked by the Michigan Department of Transportation (MDOT), which is also responsibile for the system's maintenance, either directly or through contracting with local units of government. Michigan is regarded as being the second state in the U.S. to set up a numbered and posted state trunkline system. While Wisconsin is given the credit for creating the first such system in 1917, Michigan's was organized within a year after that. Even before that point, however, in 1913 the Michigan State Legislature passed the "State Trunk Line Act," which authorized the designation of a state highway network totalling almost 3,000 miles of roadway. The act stipulated the State Highway Department would design, build and maintain highway bridges 30 feet in length or longer, if the county or local government improved three miles of adjacent road.

As of 2010, there are 122,901 miles of roads in Michigan, with responsibility for these roads divided by the state (9,655 miles), counties (90,208 miles), cities and villages (21,247 miles), and some in the federal jurisdiction (1,791 miles). According to MDOT, Michigan ranks 48th in the U.S. in percentage of roads under the jurisdiction of the state as compared to all roads system in the state (7.9%). Also, 84% of Michigan's population currently resides within two miles of a road on the state highway system.

As for the highway route designations itself, Michigan generally does not have any special "practices," such as clustering of route numbers, with the exception of what could be termed a "minimalist" strategy. This is shown when a freeway or expressway is opened along a new alignment and the former route is generally turned back to local control. However, the mileage of the state trunkline system has, itself, remained relatively constant over the last several decades, with only 500 miles separating the minimum and maximum during that time peroid. The table below illustrates this:

Total Mileage
Year
State
Trunklines
County
Roads
Municipal
Streets
Total*
1960
9,308
86,145
15,203
110,656
1970
9,221
87,723
17,847
114,791
1980
9,502
88,799
19,070
117,371
1985
9,498
88,514
19,540
117,552
1989
9,527
88,634
19,820
117,981
1990
9,538
88,705
19,877
118,120
1991
9,615
88,770
19,945
118,330
1992
9,629
88,755
20,007
118,391
1993
9,607
88,742
20,118
118,467
1994
9,591
88,836
20,155
118,582
1995
9,602
88,890
20,239
118,731
1996
9,583
89,129
20,401
119,113
1997
9,630.0
89,128.2
20,402.0
119,160.2
1998
9,725.3
89,173.8
20,500.1
119,399.2
1999
9,725.3
89,344.1
20,569.9
119,639.3
2000
9,711.4
89,498.8
20,666.9
119,877.1
2001
9,714.1
89,606.2
20,737.0
120,057.3
2002
9,711.0
89,757.0
20,784.2
120,252.2
2003
9,721.7
89,876.6
20,841.4
120,439.7
2004
9,720.8
89,898.9
20,971.1
120,590.8
2009
9,695
90,162
20,914
120,771
2010
9,655 -40
90,208 +46
21,247 +333
121,110 +339
Source: MDOT, Bureau of Transportation Planning, Asset Management Division, (517) 335-2608
*Totals do not include federally-owned mileage, such as forest roads and roads in federal installations.


MDOT
does correctly note that "the density of development varies considerably throughout Michigan, with the heaviest concentration existing in the southeast portion of the lower peninsula." Even with this obvious disparity in settlement density, there has always been a level of "geographic equity" in the organization of the state highway system. MDOT notes their aim has been to "provide everyone with reasonable access to a state highway, regardless of where they live." Over the nearly 100-year history of the signed state highway system, MDOT and its predecessors have done a excellent job of adhearhing to their goal. With the changes coming to Michigan's state highway system, the Department of Transportation is committed to maintaining this balance. However, they state "the definition of 'reasonable access' may change, more or less proportionately, for everyone in Michigan."

Additional Information

For more in-depth information about the Michigan state trunkline system, please feel free to explore the many pages on this site using the drop-down menus at the top of each page or select from any of the items below: