Impact of Wildfires on Pavement Systems

The United States has seen a recent steady increase in the intensity and size of wildfires, especially in the Western states. This is largely attributed to the impacts of climate change, which is greatly altering historic wildfire patterns by creating warmer, drier conditions and also prolonging the fire season. Wildfires can have devastating impacts on roadways, both directly and indirectly. Direct impacts include physical damage caused by flames and heat to the pavement surface and other ancillary assets (e.g., culverts). Indirect impacts can include erosion, settlement, slope instability, structural damage to the pavement structure owing to post-fire flooding and debris flow, and the damage caused owing to debris hauling and other response and recovery efforts. This paper summarizes the existing body of knowledge on impacts of wildfires on pavement systems while also identifying where gaps in knowledge and practice exist that require future research. Lessons learned from highway agency experiences in managing wildfire impacts are also discussed. Specific actions that can be taken by highway agencies today to improve the resilience of pavement systems to wildfire events are highlighted. Other topics covered in the paper include post-fire pavement condition evaluation methods, impact of response and recovery activities, and approaches to repair and rehabilitate damaged pavements.