Trucks on Missouri’s Highways

The Show-Me Institute recently hosted a panel discussion on the future of transportation funding in Missouri. An audience member asked what percentage of Missouri interstate traffic consisted of trucks. While that question received no direct answer at the time, an analysis of MoDOT’s average daily traffic maps indicates that trucks make up a significant part of interstate traffic.

MoDOT collects data on how many total vehicles pass over certain sections of the state highway system on an average day, including the interstates. In some areas they also publish the number of trucks that pass over the same section of road. Here is a chart showing truck traffic on I-70:

Total truck traffic on I-70 ranges between 7,600 and 24,000 vehicles per day on the observed segments, which on some parts of I-70 accounts for over 40 percent of total daily traffic, dipping to around 10 percent in the Saint Louis metropolitan area. Combining this data allows us to estimate that truck traffic averages 22 percent of all traffic on I-70.

The story is much the same for the other interstates in Missouri. Truck traffic can range above 40 percent of total traffic in rural areas, usually dipping to between 10-20 percent of total traffic in urban areas. The estimated percentage of total traffic from trucks across major interstates in Missouri is as follows:

For most interstates in Missouri, truck traffic averages more than 20 percent of total traffic along the length of the highway. The exception here is I-64/40, likely because it runs almost entirely through urbanized areas in Saint Louis City, Saint Louis County, and Saint Charles County.

However the numbers are sliced, trucks make up a significant portion of interstate highway traffic in Missouri. And with the average truck doing hundreds, if not thousands, of times the damage the average car does to highways, it may be reasonable to consider funding mechanisms through which shipping companies and residents can jointly invest in highway improvements.