The attached report from Transportation for America examines the condition of Michigan's bridges.  The overview of the report is as follows:

Out of 50 states and the District of Columbia, Michigan ranks as the 13th worst nationally in
overall condition of the state’s bridges.

Today, one out of every eight bridges that motorists in Michigan cross each day have some
degree of deterioration. 13.1 percent of Michigan’s bridges are rated “structurally deficient”
according to federal standards, compared to 11.5 percent nationwide. 

As of 2010, Michigan had 10,928 highway bridges: 4,402 of them owned by the state; 6,447 owned
by local counties, cities and towns; and 79 owned by other entities, such as private businesses and
federal agencies.1 1,437 of those 10,928 bridges are structurally deficient.

Michigan has 40 out of 83 counties where the average bridge condition is worse than the statewide
average.

Michigan is currently spending all of its federal bridge money on bridge repair. In 2008, Michigan
received $123 million in federal funds for bridge repair and they spent $166 million, or 20.5%
percent of all federal funds, on bridge upkeep.2 (It’s possible to spend more on bridge repair than a
state received because of other federal programs that can be shifted or “flexed” into bridge repair.)
The U.S. average is 13 percent. 

Michigan spent $48 million or 5.9 percent of all federal funds on new capacity. The U.S. average is
30 percent.