National cost impact from failing to adapt asphalt grade. Range of costs vary by year and RCP scenario considered. The projected costs are similar by RCP for the 2010–2040 period, but increases substantially by 2070–2100 period. The boxed areas enclose the 75th and 25th percentile range from t… Graphic: Underwood, et al., 2017 / Nature Climate Change

By David Trilling
13 October 2017(Journalist’s Resource) – When engineers build roads, they use weather models to decide what kind of pavement can withstand the local climate. Currently, many American engineers use temperature data from 1964 to 1995 to select materials. But the climate is changing.A recent paper in Nature Climate Change asserts that newer temperature figures are needed to save billions of dollars in unnecessary repairs. Using data from the Bureau of Transportation Statistics, Shane Underwood of Arizona State University and his colleagues show that road engineers have selected materials inappropriate for current temperatures 35 percent of the time over the past two decades.“At present, engineers assume a stationary climate when selecting pavement materials, meaning that they may be embedding an inherent negative performance bias in pavements for decades to come,” Underwood and his colleagues write. Some of their findings:

  • Failing to adapt to warmer temperatures is adding 3 to 9 percent to the cost of building and maintaining a road over 30 years.
  • The authors use two models of predicted warmer temperatures, which suggest between $13.6 and $35.8 billion in extra or earlier-than-normal repairs will be required for roads being built under the current models. In the lower-temperature warming model, this translates to an annual extra cost of between $0.8 billion and $1.3 billion; in the higher-temperature warming model, it is an annual extra cost of between $0.8 billion and $2.1 billion.
  • A road built to last 20 years will require repairs after 14 to 17 years under these models.
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Climate change costing billions in extra road repairs

ABSTRACT: Roadway design aims to maximize functionality, safety, and longevity1, 2. The materials used for construction, however, are often selected on the assumption of a stationary climate1, 3. Anthropogenic climate change may therefore result in rapid infrastructure failure and, consequently, increased maintenance costs, particularly for paved roads where temperature is a key determinant for material selection. Here, we examine the economic costs of projected temperature changes on asphalt roads across the contiguous United States using an ensemble of 19 global climate models forced with RCP 4.5 and 8.5 scenarios. Over the past 20 years, stationary assumptions have resulted in incorrect material selection for 35% of 799 observed locations. With warming temperatures, maintaining the standard practice for material selection is estimated to add approximately US$13.6, US$19.0 and US$21.8 billion to pavement costs by 2010, 2040 and 2070 under RCP4.5, respectively, increasing to US$14.5, US$26.3 and US$35.8 for RCP8.5. These costs will disproportionately affect local municipalities that have fewer resources to mitigate impacts. Failing to update engineering standards of practice in light of climate change therefore significantly threatens pavement infrastructure in the United States.

Increased costs to US pavement infrastructure from future temperature rise