In Michigan, the average state gas tax works out to about one cent per mile, assuming the typical vehicle gets an average of 24.9 mpg, which is the nationwide average. This cost is the same whether someone drives mostly on county roads, city streets or major highways. However, the cost of building and maintaining a lane-mile of an expressway is several times more than that for a lane-mile of county road or local city street.
The gas tax and diesel tax rates are also the same in Michigan, despite semitrucks doing considerably more pavement damage than passenger vehicles. According to the Congressional Budget Office, a passenger car causes minimal pavement damage compared to a semitruck, which is estimated to cause $0.21 in pavement damage per mile to rural roads and $0.66 in pavement damage per mile to urban roads. Semitrucks in Michigan do pay a higher vehicle registration fee and purchase larger quantities of fuel, but they pay the same fuel tax rate as everyone else. A better user fee would charge heavier vehicles, such as semitrucks, more than passenger cars, as they do considerably more damage to roads. Different rates could be applied to roads based on the cost to build, maintain and eventually replace them. Driving on an expressway would carry a higher per-mile charge than driving on a county road or city street.[*]
[*] Rates could also be differentiated based on peak use of roads. Higher rates could be charged, for instance, when using an expressway during rush hour. This would encourage drivers to use alternative routes or modes of travel during these periods, reducing congestion on the roadways.
 “24th Conditions & Performance Report” (U.S. Department of Transportation), pages “TypRurPvmtCostsPerLM_2018-07-26” and “TypRurCapcCostsPerLM_2018-09-28.”
 “Alternative Approaches to Funding Highways,” Congressional Budget Office, March 2011), 8, https://perma.cc/8L3A-FUBK. Note that amounts were originally reported in 2000 dollars but were converted to September 2021 dollars.