Climate change impacts on roadways

Roadways provide safe and efficient transport and are essential to the function of societies and economies. However, climate change increasingly pushes pavements beyond their engineering limits, leading to deterioration. In this Review, we explore the impacts of climate change on roadways and approaches to mitigate them. Roadways are vulnerable to changes in temperature, precipitation and sea level rise driven by climate change. High temperatures soften asphalt pavements, causing rutting, which is projected to increase by 2% per 1% increase in mean temperature. Increased moisture in the underlying soil caused by precipitation and sea level rise reduces the load-bearing capacity of roadways for months and in some cases halves their lifetime. Roadway closures due to extreme weather events or resulting reconstruction cause delays and detours; by 2100, high tide flooding in the USA is expected to cause delays of 3.4 billion vehicle-hours per year. Climate change is projected to increase national annual costs of pavement maintenance by over US$500 million on average by 2050, depending on the country. Adaptation strategies include adjusting the type of asphalt, reinforcing concrete with steel, stabilizing gravel roads and adding nature-based features. Rapid implementation of policies, guidance on evaluating adaptation alternatives and exploration of the combined impacts of multiple climate stressors are needed. Roadways are damaged by temperature extremes, increased precipitation and sea level rise. This Review discusses the mechanisms and impacts of climate stressors on roadways, the resulting operational and maintenance challenges, and strategies to increase resilience.