This bill, known as the Heat Emergency Assistance for Transportation Act of 2025 or the HEAT Act of 2025 , aims to expand federal emergency relief to cover damage caused by extreme heat to transportation infrastructure. It amends Title 23, United States Code, specifically section 125, to explicitly include "extreme heat" as a qualifying event for emergency funding, alongside other natural disasters like severe storms and flooding. This change addresses the current omission of extreme heat from federal disaster programs, despite its documented impact on critical infrastructure. The legislation also mandates a comprehensive study by the Transportation Research Board of the National Academies to evaluate the measurable costs of extreme heat events and recommend methods for tracking heat-related damage, distinct from regular deterioration. This study will also examine how the Secretary of Transportation can better assist state departments of transportation and other entities in monitoring such damage. Furthermore, the Secretary of Transportation is required to issue a report on best management practices for highway and bridge safety to reflect new information and advancements related to extreme heat within one year of the bill's enactment.