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.
- In some cases, government transportation agencies are paying too much for materials to withstand cold temperatures that do not currently (and perhaps no longer) exist.
- Because municipal governments in the United States work on tighter road-maintenance budgets than state and federal transportation departments, the extra financial strain will largely impact cities and towns.