The Road Information Program (TRIP), a well-regarded nonprofit association financed by the highway construction industry has done a number of studies of national and individual state road conditions, operating characteristics and funding needs. In 2004, TRIP concluded Michigan state roads were underfunded by $700 million per year, with county/city roads under-funded by another $2 billion per year.[61] The TRIP analysis did not consider funding needs for urban interstates in southeast Michigan, so I-75/I-94 investments that will be in the billions of dollars are not included in the $700 million estimate.

The TRIP report was, however, completed prior to the passage of SAFETEA-LU so it does not take into account the additional $193 million per year that the act authorized for Michigan highways. At the same time, not all of the authorized aid is being appropriated, with Michigan expected to get just 80 percent of authorized levels, or about $154 million per year. After the 75/25 state/local split that results in an additional $115.8 million for state-owned roads over and above the level of funding when TRIP did its needs analysis. Taking that extra funding into account would lower the TRIP assessment of state road funding needs to $584.2 million, with local needs reduced to $1,961.5 billion.

The Reason Foundation, another outside organization that has studied Michigan road funding, found the state needs to spend an additional $27 billion by 2030, or about $1 billion per year more.[62]