Show Me the Money: Expanding Interstate 70

The highway money, that is. Missouri is doing just that with its ambitious plan to widen I-70 to at least six lanes across the state’s breadth.


Like a steely-eyed riverboat gambler, Gov. Mike Parson pushed $859 million in chips to the center of the table in early 2023. He was betting that the Missouri General Assembly would go along with his call to make Interstate 70 a six-lane highway between Blue Springs and the St. Louis suburbs.

The legislative reply: “We’ll see your $859 million . . . and raise you $2 billion.”

With that, the 2023 session in Jefferson City produced the largest single public works project in Show-Me State history. Lawmakers signed off on a $2.8 billion package that would add a third lane in each direction between the exurbs of St. Louis and Kansas City. For now, the only stretch of that road that features additional lanes runs for just a few miles through Columbia.

The scope of the project, in a word, is unprecedented, just as it was nearly 70 years ago, at the dawn of the interstate highway age.

Right From the Start

Congress approved the first funding for a nascent interstate system in 1956, and almost immediately, Missouri was part of the conversation: The first construction contracts for this new interstate system were awarded in August of that year in Missouri, starting with a portion of I-70 in St. Charles County. 

That was just weeks after President Dwight Eisenhower called for the construction of a 41,000-mile system of Interstate highways, paid for with fuel taxes on motorists and states picking up 10 percent of the cost. The federal government would pay 90 percent of the initial construction costs.

Missouri wasted no time getting the road graders fired up. On Aug. 13 of that year, the first interstate construction project in the nation began on a part of U.S. 40 that would be redesignated Interstate 70 in St. Charles County. The $1.87 million project—about $20.9 million in 2023 dollars—included 3.1 miles of bridging, grading, and concrete paving.

Flash forward nearly 70 years later, and the money authorized by the state in 2023 isn’t coming a moment too soon. Steve Miller, the former chairman of the Missouri Highways and Transportation Commission, rang the alarm bell on I-70’s condition back in 2015.

The interstate, he wrote, “has become a huge liability. Its original pavement is shot, held together by years and years of overlays. The original pavement and base—some of which dates back to sections of old U.S. Route 40 that was built in the 1920s—have been pounded to bits by years of mounting traffic, heavier loads, and increased tire pressures. Its bridges are nearing the end of their useful lives. It carries far more traffic than it was designed to. Congestion is mounting. The increasing mix of long-haul trucks with cars makes people nervous and concerned for their safety.”

Dovetailing with Miller’s call to action a few years later, the national transportation research non-profit TRIP placed Missouri in the Top 10 nationwide for the number of interstate bridges that were either in poor condition or structurally deficient: One in 20 statewide.

Many of the first interstate bridges built had a life expectancy of 50 years; the average age for those in Missouri’s system is bucking up against that threshold at 48 years. And more than half, 56 percent, of the state’s interstate bridges, have exceeded that original life expectancy.

Beyond safety and convenience, I-70 is arguably the backbone of interstate commerce in Missouri. The importance of interstate lane miles to the state’s economy is enormous: Those freeways make up just 2 percent of all roadway lane miles in Missouri, but carry 27 percent of vehicle travel statewide, TRIP estimates. That comes to 21.5 million vehicle miles of travel annually.

Moreover, the large trucks that carry the majority of freight shipped in the U.S. accounted for 17 percent of all vehicle miles of travel on the state’s highway system before the 2020 pandemic struck. That ranked Missouri No. 9 nationally in that metric.

All told, more than $480 billion in goods are shipped every year to and from sites in Missouri, and the vast majority of that is done by truck—67 percent. 

Among other findings by TRIP:

• Completion of the nation’s interstate system—including the 260 miles of I-70 in Missouri that account for nearly 12 percent of that roadway’s 2,172 miles—lowered the cost of moving freight from 16 percent of U.S. GDP to 8 percent in 2018.

• U.S. counties within 20 miles of an interstate grow much faster than others outside those corridors: By 2060, it’s estimated, they will grow roughly seven times the outsiders—36 percent, vs. 5 percent.

• Travel times between destinations throughout the U.S. have been sharply reduced. That, TRIP says, has given Americans greater choices about where they live, work, shop and spend their leisure time. 

A final point worth noting, according to St. Louis Regional Freightway, is that carriers on I-70 haul 100 million tons of freight each year, valued at $154 billion. Roughly 30 million tons of that is just passing through Missouri, as is the majority of valuation, nearly $93 billion.

More than simply connecting the state’s two major centers of commerce—Kansas City on the west and St. Louis on the east—I-70 provides links to a number of vital commercial corridors serving other parts of the state and, eventually, other states throughout the Midwest.

Among them are I-35 in Kansas City, dubbed the nation’s Superhighway linking Mexico to the Great Lakes and Canada; I-49 from Kansas City south to the Gulf region in Louisiana; and just across the Mississippi River from Saint Louis, I-55 to Chicago, Memphis, and New Orleans, and I-64 to Nashville and connections to the southeastern United States.

Making a Difference

Numerous studies have suggested that simply adding a lane to long stretches of interstates will provide short-term relief from traffic congestion. But increased economic activity spurred by access to a six-lane highway will eventually increase traffic to the point where motorists and carriers will experience the same time delays they face on four-lane infrastructures. 

Which begs the question: If Missouri is going to grow, wouldn’t inaction further exacerbate the challenges it has with traffic flows today? The answer to that question lies 500 miles to the northeast: Any-one who has witnessed the “flow” of traffic in and around Chicago knows the opportunity cost of freight significantly delayed by unending traffic jams.

Just as anyone who has taken I-70 east from Blue Springs or west from Wentzville knows that the next 188 miles of high-speed travel will require additional diligence behind the wheel, navigating an endless stream of 18-wheelers and construction delays before reaching the relief of six lanes of pavement, or more, on the approaches to Kansas City and St. Louis.

For them, 2031 can’t come soon enough: That’s the earliest projected completion date for a six-lane I-70, assuming actual construction, as projected, begins in 2024.