Truck traffic has also grown very rapidly. Nationally, between 1980 and 2002, truck travel grew by more than 90 percent while lane miles increased just 3 percent. Growth in traffic is expected to continue. Overall U.S. truck traffic is expected to grow 92 percent between 1998 and 2020, with the percent of urban interstates carrying 10,000 or more trucks per day expected to grow from 27 percent in 1998 to 69 percent in 2020.
In 2003 Michigan’s multi-modal transportation system moved approximately 670 million tons of freight with an estimated value exceeding $1 trillion, with 70 percent of that weight moving by truck. Looking just at the truck mode, 40 percent of that tonnage moves wholly internally within the state, with 53 percent moving into or out of the state, and just 7 percent moving through Michigan with no origin or destination in-state.
Table 6 also summarizes Michigan’s state trunkline commercial vehicle miles traveled (CVMT). Data for non-trunkline travel is not available. Between 1995 and 2004, CVMT grew 20.8 percent, but miles grew just 1.4 percent. Going forward, MDOT estimates CVMT will grow, from 2004 values, 15.2 percent by 2015, and by 39.4 percent by 2030. If no new miles are added we would have had a 68.5 percent increase in CVMT between 1995 and 2030 with just a 1.4 percent increase in mileage.
Figures 12 and 13 visually portray the expected changes in truck average daily traffic between 1998 and 2020 in various areas of the state.