In Michigan you are typically found to be more than 50% at fault for incidents such as hitting a tree, a person or another vehicle. A driver is normally found 50% or less at fault for accidents if you are rear-ended, side swiped, etc by another driver.
From these definitions found on the Michigan Office of Financial and Insurance Service, it would appear that a motorist of a vehicle that hits a hole in the roadway or shoulder would be found to be at fault. The driver in this case might have been able to avoid the hole and thus may be found by their insurance company to be 50% or more at fault.
To be found 50% or less at fault it seems that it would need to be another person doing the damage to your vehicle such as a person who hits the back of your vehicle at a stop light.
To find out more about how fault is determined in Michigan, speak with your insurance agent or the MI Insurance Services consumer division. For an affordable Michigan automobile insurance quote, click here.