Policy Study

Mobility Project – State-by-State Analysis of Future Congestion and Capacity Needs – Missouri

Reason Foundation
Mobility Project

Traffic Congestion in America’s Cities


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How bad will traffic congestion be in 2030? How much construction and how many new lane miles will each state and major city need to add over the next 25 years to prevent severe congestion? And how much will it all cost? The Reason Foundation study Building Roads to Reduce Traffic Congestion in America’s Cities: How Much and at What Cost? and its addendum, A Detailed State-by-State Analysis of Future Congestion and Capacity Needs, provide in-depth answers to these questions. An interactive map ranking the states by congestion and costs to reduce traffic is here and a map of the most congested cities is here.


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To significantly reduce today’s severe congestion and prepare for growth expected by 2030, Missouri needs just over 1,970 new lane-miles at a total cost of $4.6 billion, in today’s dollars. That’s a cost of approximately $42 per resident each year. Missouri ranks 15th out of 50 states and the District of Columbia in terms of most lane-miles needed and 20th in the total costs of those improvements. If the state made these improvements, it would save over 79 million hours per year that are now wasted in traffic jams.

Missouri has one city that currently suffers from severe congestion, which this study identifies as those areas with Travel Time Indices (TTIs) of 1.18 or higher. The St. Louis area on the eastern edge of the state is tied with three other cities (Memphis, San Antonio and Cincinnati) as the 35th most congested region in the United States, with a Travel Time Index (TTI) of 1.22. This means that driving times during peak traffic hours are 22 percent longer than during off-peak times.

Unless major steps are taken to relieve congestion, drivers in St. Louis can expect to see a TTI of 1.42 by 2030. For an idea of how severe that level of congestion would be, note that this projection is worse than the traffic delays experienced today in all but five cities in the United States: Atlanta, Washington, DC, Chicago, San Francisco and Los Angeles.

As Table 31 suggests, the picture is a little better for Kansas City which is projected to see a TTI of 1.33 by 2030, which reflects traffic delays similar to those experienced currently in the larger cities of Tampa-St. Petersburg and Minneapolis-St. Paul.

But Missouri can significantly reduce these congestion problems by adding about 1,970 new lane-miles by 2030 at an estimated cost of $4.6 billion in today’s dollars. This investment would save an estimated 79 million hours per year that are now lost sitting in traffic, at a yearly cost of $2.32 per delay-hour saved. This does not account for the additional benefits not quantified in this study, including: lower fuel use, reduced accident rates and vehicle operating costs, lower shipping costs and truck travel time reductions, greater freight reliability, and a number of benefits associated with greater community accessibility, including an expanded labor pool for employers and new job choices for workers.

The other cities in Missouri with populations above 50,000 (Springfield, Columbia, St. Joseph, and Joplin) are currently much less congested than St. Louis and Kansas City, with TTIs in the 1.04—1.05 range. However, the relative increase in delay projected over the next 25 years for these cities is still quite high, at 100 percent or more. Such a significant increase will be sharply felt by local commuters. (The ‘delay’ in the travel time is the portion of the TTI over 1.0.) With TTIs of 1.08 and 1.09, small cities like St. Joseph and Columbia are facing future traffic delays similar to those currently experienced in much the much larger cities of Dayton and Cleveland, respectively.

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» Return to Index Page: Study, State-By-State Data, Maps
» Return to Interactive Map of Traffic U.S. Congestion Statistics and Construction Needs

This information is excerpted from A Detailed State-by-State Analysis of Future Congestion and Capacity Needs and Building Roads to Reduce Traffic Congestion in America’s Cities: How Much and at What Cost?

Additional Resources:
» Reason Foundation’s Mobility Project Main Page
» Reason Foundation’s Transportation Research and Commentary
» Reason Foundation’s Press Room

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