Extreme heat impact on road infrastructure and safety

Extreme heatwaves are causing significant damage to road infrastructure by altering the physical properties of pavement. In the southern United States, high temperatures led to asphalt softening and breaking apart on U.S. Route 69 in Texas, as well as concrete buckling on Interstate 49 in Louisiana.

Rising ambient temperatures can cause asphalt surfaces to exceed 60 degrees Celsius, softening the bituminous binder. This process, exacerbated by heavy vehicle traffic, results in permanent ruts and depressions. Experts, including Lidija Ržek from the Institute for Construction in Slovenia (ZAG), note that these deformations are increasingly driven by climate-related heat stress rather than just age or traffic volume. These ruts also pose safety risks, such as increased hydroplaning during heavy rainfall.

In Europe, municipalities like Maastricht in the Netherlands have begun spreading salt on roads to mitigate these effects; the salt attracts moisture to help lower asphalt temperatures and reduce bitumen stickiness. This is particularly useful at intersections and roundabouts where frequent braking and acceleration increase the risk of deformation. However, the Dutch national road administration, Rijkswaterstaat, avoids this practice on motorways because much of that network utilizes porous asphalt, which is less sensitive to high temperatures.

Beyond infrastructure, extreme heat impacts vehicle safety. High temperatures increase the risk of tire issues when combined with high pressure, low pressure, overloading, or high speeds. Experts advise checking tire pressure when tires are cold and warn against using winter tires in summer, as their softer compound can compromise handling and braking on hot asphalt. To address these risks, engineers are exploring new asphalt mixtures and advanced diagnostic tools like laser scanners, sensors, and cameras to detect overheating sections before they become hazards.