By Robert W. Poole Jr.

Every year the Texas Transportation Institute’s Urban Mobility Report has a little section that shows, with real numbers, that those urban areas which came the closest to keeping highway capacity growing in pace with vehicle miles traveled (VMT) had the smallest increases in congestion.

But more and more of America’s metropolitan planning organizations (MPOs) have been ignoring this point.

In a new Reason Foundation study, David Hartgen and Greg Fields of University of North Carolina at Charlotte show that the long-range transportation plans of many urban areas downplay highway expansion, devoting well over half their total planned spending over the next 25 years to non-highway aspects of transportation (www.reason.org/ps346.pdf).

This is true not just in those places with traditional central business districts where transit can play a meaningful role (e.g., New York, Chicago, Boston) but also in large suburbanized areas such as San Jose, Salt Lake City, Charlotte and San Diego, where transit can serve only niche markets.

What’s happened over the past two decades is the triumph of the idea that “we can’t build our way out of congestion,” and hence that the only sensible policy is demand reduction.

That accounts for the tremendous shift of resources from highways to transit, bike paths, and smart growth. The idea is that by dramatically reducing demand (VMT), we can thereby reduce congestion.

Except that somewhere along the line, many of these same MPOs seem also to have lost sight of reducing congestion. As Hartgen and Fields note, in many long-range plans this no longer appears even as a goal. And if the plan’s authors are honest enough to include their projected conditions in 2030, most show that congestion will be even worse than today’s intolerable levels.

What this new study sets out to do, then, is to ask and answer the question: What if we wanted to expand highway capacity in response to the demand that’s clearly there?

More specifically, Hartgen and Fields worked with 32 MPOs to run their traffic assignment models so as to answer the question: How many lane-miles would you need to have, by 2030, to eliminate all serious congestion (defined as Level of Service F)?

Georgia urban areas ranked 10th in the nation for lane-miles congested by 2030, at 1,516 lane-miles, and relieving congestion would require adding 3,220 lane-miles by 2030.

Then, using generic cost data for various types of lane-miles (freeway, major arterial, etc.), they estimated what it would cost to add this capacity over the next 25 years. Finally, using some rather clever techniques, they extrapolated these results to all 403 urbanized areas in the United States. Georgia’s cost to add the needed capacity would be $14.3 billion, and Atlanta’s share of that would be $13.1 billion, they found.

Overall, the resulting numbers for the nation look big at first glance: 104,000 added lane-miles costing $533 billion in 2005 dollars. But they aren’t really that large when put in perspective.

That cost of $21 billion per year is about 10-15 percent of already planned highway spending. It’s about 28 percent of current MPOs’ long-range transportation budgets.

Thus, if none of the existing budget allowed for highway capacity expansion, the worst-case spending increase would be 28 percent.

But in fact, most of these plans include some highway capacity additions, especially HOV lanes. And most of them include large sums that do little or nothing to reduce congestion, which conceivably could be shifted to capacity expansion, so the net cost increase might be zero.

What about the benefits? The researchers estimate (based on the modeling results) that by 2030, nationwide travel time savings would be 7.7 billion hours per year. The cost of producing those savings varies considerably from city to city, ranging from as little as 9 cents per trip to about 75 cents per trip (in large cities). Overall, the average cost per hour saved is $2.76, far below even very conservative estimates of the average value of people’s time.

Atlanta would see a 27.2 percent reduction in peak-period travel times and a 36.5 percent increase in peak-period speed, saving regional commuters about 1.61 million hours a day in travel time, the study estimates. “At a conservative $12 an hour, time savings would be valued at $96.6 billion over 20 years,” the researchers report.

“Savings from reduced operating costs and reduced fatal accidents would bring the total savings to $98.6 billion. Compared to the implementation costs of $13.1 billion, this is a substantial benefit.”

To be sure, we know that incident-related congestion amounts to about half of total congestion, so adding capacity is not the only solution. But the study paper makes a solid case that it can be a major part of the solution.

Robert W. Poole, Jr. is director of Transportation Studies at the Reason Foundation and an adjunct scholar with the Georgia Public Policy Foundation. The Georgia Public Policy Foundation is an independent think tank that proposes practical, market-oriented approaches to public policy to improve the lives of Georgians.

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