A heat wave in the eastern United States over the Fourth of July weekend in 2026 caused roads to buckle. Extreme temperatures led to one lane of traffic on Interstate 97 south of Baltimore to warp, resulting in its closure due to heat damage. City streets in Chicago also experienced pavement failure during this period. Several state departments of transportation advised motorists to be aware of further heat-related road damage.

"Heat-related road failure occurs when moisture-weakened pavement gets hot, expands, buckles and warps — especially if the high temperatures last for several days," said Charles Marohn, founder and president of Strong Towns. "When water gets underneath a roadway, it'll get a little bit squishy, and instead of being firm, it'll start to move a little bit." Marohn added, "Any time you design an asphalt or concrete mix, you're designing for a certain range of temperatures. Extreme events expose the limits of those assumptions." He noted, "It goes really bad, really quick."

"You take that prolonged period of just intense heat, a lot of traffic on top of it, and that's when you have something like this happen," said Charlie Gischlar, spokesperson for the Maryland Department of Transportation. Amit Bhasin, a professor of civil, architectural, and environmental engineering at the University of Texas at Austin, indicated that heat-related road failure is typically an issue with concrete pavement. "It expands more than what it's designed for, [so] it's going to buckle," Bhasin said. "What you see is [that] … ruts form, especially in slow-moving traffic areas. It tends to be … like a liquid under a hot summer afternoon."

Bhasin identified a lack of weather and climate data as a problem for road design. "If there is a trend that predicts different kinds of extreme event scenarios, then those should be incorporated into the pavement design," he said. Mikhail Chester, a professor of engineering at Arizona State University, stated, "In many ways, we've designed our infrastructures over decades, if not centuries, for temperatures that have been relatively milder. Now, as temperatures are hotter, you're starting to see the dynamics of those extremes take hold, exceeding the design thresholds of those infrastructures and their particular assets." Chester added, "And that's going to require us to innovate, which we are doing. It's going to require us to share that knowledge, which we're starting to do."

Steel rebar or expansion joints can be incorporated between concrete panels to account for expansion. "If you're using reinforced steel, then you would want to consider different percentages of steel reinforcement," Bhasin said. "If you're applying joints, then perhaps [engineers could use] … a slightly different joint spacing ... or changing the size of the panels themselves." However, Bhasin cautioned, "You don't want to provide too much of it because then you affect ride quality." Designing roads for extreme events would result in higher costs. "So you have to make the call that 'I'll be OK if 99% of the time this works and maybe 1% of the time the traffic is disrupted,'" Bhasin said. Asphalt roads are generally less expensive initially but typically require more frequent repairs compared to concrete, which has a longer service life. "Engineers have figured this out, and they can design it," Bhasin said. "They just need to know what to go off of."