Between 1982 and 1992, the number of miles driven on Michigan roads increased by 37.0%, placing additional demand on the system.25 Since 1982, the number of registered vehicles rose 13.7%. The increase in travel and registered vehicles produced an increasing need for capital projects and maintenance, but the increased traffic also led to increased revenues. Michigan Transportation Fund revenues increased 46.9% in real terms between 1982 and 1992, substantially exceeding traffic growth rates and inflation. Real revenue grew by 14.0% between 1987 and 1992 during a period of slower nominal revenue growth. These traffic increases do not justify an increase in taxes to fund incremental investment, even though they do create additional need.

Fixing poor roads is three to five times more expensive than fixing fair condition roads so it is important to halt the deterioration of fair roads.

Some of the best support for incremental investment in the highway system comes from the road and bridge condition data. On the state trunkline system the percent of "poor" state system roads increased by 36.0% between 1982 and 1993, and the percent of roads rated at least "fair" decreased by 47.0% over the same time period. On the other hand, the percent of roads rated good increased by 92.0% during this time. As shown in Figure 8, as of 1993, some 36.5% of state trunkline roads were rated poor and 24.9% were rated fair.26 Fixing poor roads is three to five times more expensive than fixing fair condition roads so it is important to halt the deterioration of fair roads. The 36.5% of Michigan trunkline roads rated poor compares to a national average of 8.4%.27 Michigan also has a slightly higher percentage of deficient bridges on the state system compared to other states, with 37.6% rated deficient. On the county road system a recent survey of county road commissions by the Road Information Program found that 32% of county roads are claimed to be in poor condition, with 40% rated in fair condition.28

The information on road and bridge conditions tends to support the need for additional investment in maintenance and reconstruction to slow the growth in the percentage of "poor" roads. Future investment costs will be substantially reduced if roads can be repaired while they are still in fair condition. Repairs to the existing road network can also help lower maintenance costs for automobile owners. According to calculations by The Road Information Program in their report for the Michigan Road Builders Association, the Congressional Budget Office has calculated that the "variable cost to operate vehicles was 11% higher on fair roads than on roads in good condition, and 29% higher on roads with poor surfaces." Using this information, Michigan motorists are spending $679 million more per year to operate on our substandard state road system, or $105.43 per driver per year.29 Although this estimate may somewhat exaggerate the cost claims, it seems plausible that there is a cost penalty of higher repair costs, increased fuel use and increased tire wear.

The congestion on Michigan roads could also be an indicator of need. Michigan's major urban roads are quite congested. The Federal Highway Administration considers an urban road with a volume capacity ratio above 0.80 to be congested.30 62.9% of the urban interstate system exceeds this standard, along with 45.9% of "other principal arterials." For all major Michigan urban roads, 49.5% are considered congested. This compares to a national average of 29.9% of major urban roads being congested, and a Great Lakes state average of 31.0%. Overall, Michigan has double the national average percentage of major urban roads that are considered "congested." However, "congested" is a term of art that simply means volumes exceed 80% of capacity on average. It does not necessarily correlate to hours of delay, which is more dependent on peak hour traffic flows relative to capacity. Nonetheless, it is clear that about half of Michigan's major urban roads are close to theoretical design capacity.

A comparison of Michigan's roadbuilding and maintenance spending with that of other states also provides insight into whether there is a need for additional investment in Michigan's road system. Michigan's overall spending levels are well below the national average, with state and local spending of $208 per person ranked 46th in the country according to Public Sector Consultants, Inc.31 Michigan's roadbuilding and maintenance spending equal to 1. 1% of personal income ranked 47th in the country. Finally, on a per mile basis, PSC reports that Michigan's capital outlay spending of $5,420 ranks 30th in the country, and that the $1,181 of maintenance expenditures per mile rank 37th in the country.

What do these figures tell us? The fact that Michigan spends less than other states does not necessarily mean that we should raise our spending and taxes to their level. It may instead be a reflection of Michigan's earlier commitment to major roadbuilding in the 70s and 80s compared to other states, or a reflection of greater efficiency in Michigan transportation investment compared to other states. The per capita and personal income comparisons may also reflect the fact that we can spread our expenditures over a larger population base than other states, and that we have personal income that is higher than most states. However, the very low level of spending compared to other states is probably some indication of a need for additional spending to avoid falling behind other states on the quality of our transportation infrastructure.