Bats regularly use bridges and other transportation structures for roosting in the United States, especially in warmer climates like the southeast. Recent surveys in Georgia suggest that roughly 17% of inspected bridges and culverts have some evidence of bat use. During a survey for a large interstate maintenance project in 2015, the largest known bridge roost in Georgia was discovered. Thousands of big brown bats (Eptesicus fuscus) and Brazilian free-tailed bats (Tadarida brasiliensis) are found year-round on this bridge located in northwest Georgia. Although these species are considered common and are not listed as threatened or endangered at the state or federal level, the intentional take of any bat species is a violation of state law in Georgia. Further, because of the structure of the bridge and the large numbers of bats in the joints, the potential presence of federally protected species could not be ruled out. Georgia Department of Natural Resources and US Fish and Wildlife Service biologists deemed traditional exclusion methods unsuitable for a colony of this size and worked with the Georgia Department of Transportation to develop a plan for completing necessary maintenance at this site without harming the bats. Using special provisions, hands-on assistance, and small changes to the normal maintenance plan, the project was completed in 2018. This project provided an opportunity for engineers and biologists to test the effectiveness of using backer rod for protecting bats still present in the expansion joints while completing joint replacement and resurfacing. These small changes did not add significant costs or delays to the project and no injury or mortality of bats was observed during the process.