December 14, 2018

Few things are more American than the Interstate Highway System. Conceived to facilitate commerce across state borders and connect the country, the Interstates are ingrained in how we commute, how we shop, and how we participate in society. But now that many segments are more than 50 years old, the system needs a rebuild. A major project from the Transportation Research Board (TRB) recently set out to reimagine the Interstate Highway System to meet 21^st century needs.

Congress commissioned TRB to study “the actions needed to upgrade and restore the Dwight D. Eisenhower National System of Interstate and Defense Highways to its role as a premier system that meets the growing and shifting demands of the 21st century.” To its credit, the final report addresses some of the most challenging questions facing the Interstates, including a clear, no-nonsense case for the renewal of the physical infrastructure of the Interstate system. Rebuilding the aging bridges and roadbeds will be incredibly painful and expensive for the country, particularly as our economy has become reliant on the Interstates for commuting, freight movement, and other everyday activities.

But the report falls short of expectations as it takes a conservative, engineering-based approach that reiterates the industry’s talking points from the past 25 years. In summary, it recommends a new federal program to cover 90 percent of the cost of reconstructing the entire Interstate Highway System and widening it where congested, paid for by an increase in the fuel taxes (and perhaps, possibly, maybe one day a vehicle-mile-traveled fee). And while rebuilding, it advises “right sizing” the system, adding segments to connect more of America and, in some cases, remove sections in urban areas. (for more detail, see full coverage in last week’s Eno Transportation Weekly)

A report on the future of the Interstates needs to be bolder in vision. For example:

Increase capacity without widening.

The report frequently calls for expanding capacity, lumping reconstruction and widening into the same recommendation. But report after report, study after study, (many published by TRB) conclude that widening does not decrease congestion and is a terribly inefficient way to expand regional access to economic opportunities. With growing populations and expected growth in vehicle miles, a business as usual approach to the Interstates is hopeless and irresponsible.

Engineers, planners, and researchers need to be creative about how to address congestion and increase accessibility without adding more pavement. True interstate and regional commerce involve moving people and goods, not cars and trucks. The report includes some minor discussion of pricing via tolls and managed lanes, but this needs to be a highlight and its recommendations should encourage these as primary strategies. The transportation system cannot handle the status quo given the expected growth in population and vehicle miles.

Reconcile the Interstate’s contribution to climate change.

The report rightly attributes the Interstates with exacerbating climate change. According to the report, travel on the Interstates alone counts for 7 percent of total US carbon emissions, not including the other travel that they enable to and from the highways on local streets. Buried in the text is a stark finding:

“The choices being made now and in the next few decades about GHG emissions from fossil fuel and land use changes will influence the extent of additional warming over this century and beyond. … Given that motor vehicles account for about 25 percent of U.S. GHG emissions and that about a quarter of VMT is on the Interstates, the future use of the Interstate System will be an important part of this choice set.”

But in response the report only recommends that states make their Interstates more resilient to withstand the extreme weather events they are causing. While of course we should be planning more resilient infrastructure, forward thinking on the Interstates should address the need to reduce its impact on the environment while still contributing positively to the US economy. The report’s scope did not include alternative fuels, but it could have recommended strategies like reducing speed limits, incentivizing states to implement road pricing, and encouraging more carpooling. Fuel taxes are better thought of as carbon taxes in this context, rather than an easy way to raise money for roadway improvements.

Recognize the Interstate’s spillover safety effects.

The report consistently states that the Interstate system is the “safest roadway” in the country, when measured as crashes and fatalities per mile traveled. But safety is declining on the Interstates and surrounding roadways as total fatalities increase. Interstates in urban areas transition high speed traffic onto busy city streets and lower speed roads. And the trend of increasing speed limits is cutting into its safety record: When Ohio increased speed limits from 65 to 70 miles per hour on some of its Interstates in 2013, deaths on those segments spiked 22 percent.

The safety recommendations in the report hinge on the successful implementation of connected and automated vehicle technologies. While these technologies show promise, their safety benefits are years away from being realized. In the meantime, federal programs should incentivize actions that reduce fatalities by reducing speeds, minimizing conflicts, and allowing safe vehicle operations throughout the system.

Emphasize eliminating some Interstate segments as part of “right sizing.”

The report recognizes the negative impact that the Interstates have had on urban communities and recommends that the federal government develop metrics to determine where to grow the Interstate system and where to downsize it. But the proposed policies place more emphasis on building more Interstate mileage and maintaining what already exists.

Right sizing, particularly in the face of massive reconstruction costs, should encourage rethinking significant portions of Interstates in urban areas. This does not mean removing them completely as a thoroughfare, but conversions into boulevards and other roadways can help reknit divided neighborhoods, save substantially on costs, and still provide a viable route for commuters. But the report’s federal reconstruction program would pay for 90 percent of the cost of rebuilding and expanding, providing a huge incentive to maintain the status quo. Perhaps that same money should be also available to encourage and pay for conversion.

Part and parcel of that would be to conduct a full analysis of the real purpose of the Interstate Highway System. For freight traffic, the system undoubtedly serves an important, long-haul role in interstate commerce. But the report recognizes that Interstates have become “primary corridors for commuting and other local travel,” a far cry from its original intent. Vehicle miles on urban Interstates account for 70 percent (and growing) of all Interstate traffic, while rural Interstate vehicle miles peaked in the early 2000s. If so much travel is inherently local, perhaps the designated Interstate system should only apply to segments that are primarily for Interstate travel.

On the other hand, expanding the length of the system will do little to bring widespread economic benefits to the country. Regions that are farther than 25 miles from an existing Interstate, which the report enumerates, want the Interstate brand and the federal dollars that go with it. But these communities already have high capacity, limited access roadways that serve them and connect them Interstates and other national roadways. From a transportation standpoint, expanding the system to connect them does little to boost the economy and regional accessibility.

Perhaps Congress and the TRB steering committee considered more revolutionary recommendations but did not find them feasible. Or perhaps they did not want to wade into making some tough recommendations on the system’s future. But the intractable problems of the future of transportation are going to be solved with fresh thinking, not just fresh concrete.

The opinions expressed above are those of the author and do not necessarily reflect those of the Eno Center for Transportation.