TRB Report Looks at Deteriorating Interstate Highways

Posted by in potholes

Interstate highways get a much higher load of traffic, particularly in the eCommerce era vs. when they were built, causing expensive wear and tear. One solution: end the ban on interstate tolls?

Here are a few facts anyone with an interest in better pavement, fewer potholes, and interstate highway travel should note:

• Over the last three-and-a-half decades (from 1980-2015), vehicle miles traveled on interstate highways grew by 160 percent. On all other public roads the growth was 90 percent.

• Interstate highways carry 25 percent of all vehicle miles traveled, but constitute only 1 percent of public roadways in America.

• Half of all miles traveled by heavy trucks – the kind that cause the greatest wear and tear on asphalt – are on interstates.

Add to all that a green argument for raising truck load limits by 50 percent. The result: More pavement stress and more potholes.

These and a few other sobering statistics were reported recently (December 6, 2018) by the Transportation Research Board (TRB), a program unit of the National Academies of Sciences, Engineering, and Medicine. The academies provide independent, objective analysis and advice to the country under the sponsorship of 12 federal agencies (FAA, FHWA, FTA, DOE, DOI and EPA among them) as well as private agencies (American Public Transportation Association, et al.).

The report, Renewing the National Commitment to the Interstate Highway System, states “the future of the U.S. Interstate Highway System is threatened by a persistent and growing backlog of structural and operational deficiencies and by various looming challenges.”

How to pay for pothole fixes on those interstates

The report’s prescription for fixing this requires more money, of course: $45 billion to $70 billion per year more than the current $25 billion to renew and modernize existing highways.

Where will that money come from? The report recommends starting with an increase in the federal fuel tax – currently a per-gallon charge of 18.4-cents and 24.4 cents for diesel fuel – which has been frozen at the same level since the 1993. In the quarter century since then gas prices rose, fuel efficiencies increased, and more traffic plied those highways, all adversely affect gas tax revenues and maintenance expenses.

Another means for paying for smoother pavement recommended in the report is to collect tolls or impose per-mile charges on interstate users. Currently most highways in the interstate system have a ban on tolls; lifting that ban would enable states and metropolitan entities to also raise revenue. A lynchpin to this plan overall is to join federal and state governments to work in partnership and share toll revenues. Presumably local governments would allocate those revenues to secondary road maintenance. Reportedly, some secondary roads receive interstate traffic due to congestion on the federal system.

eCommerce increases truck traffic; and larger loads use less fuel

Along with natural population increase – which has been around 0.8 percent since 2000 – the rise of ecommerce and fast package deliveries are reasons for increased truck traffic and traffic overall on all roadways. Near bigger cities, population growth rates are higher as is use of online shopping to get everyday household goods. These effects are greatest in the crossroads regions where warehouses are most efficiently placed.

The TRB reports that climate change can play a role in the devolvement of infrastructure, as storms, increased rainfall (in some areas), and extreme temperatures (hot and cold) and temperature fluctuations damage bridges and pavement.

Environmental concerns play into the report and the overall conundrum of how to support commerce in the greenest ways possible. The rise of electric vehicles reduces gas consumption, but with that a reduction in revenues from gas taxes. Faster deliveries further reduce use of railways, a greener means of transporting goods but less suited for speed.

The federal highway system prohibits the size and weight of vehicles to 80,000 pounds. But the trucking industry now lobbies to increase load size with an argument that it’s actually greener to do so. For example, if 80,000 pounds can be increased to 120,000 pounds, that will reduce the amount of gasoline consumed per pound of freight.

Still, heavier trucks cause more damage to pavement, which then increases the number of potholes.

Shifting population, shifting highway priorities

The TRB report urges Congress and the U.S. Department of Transportation and Federal Highway Administration to “rightsize” the interstates, particularly around crowded urban corridors. That may mean adding lanes and interchanges.

Also recommended is that all local and national jurisdictions begin to plan for automated and connected vehicle operations. Encouraging further research and updated standards should “ensure that basic intelligent transportation system instrumentation is adopted on a consistent and system wide basis,” says the report. “Uniformity and other attributes of pavement markings, interchange design, and the like are capable of facilitating eventual interstate use by connected and automated vehicles.”

The times they are a-changing for sure. Whichever means are found to modernize the roads, it’s clear we can’t do it with potholes in the pavement.