Bats in American Bridges

Bridges and culverts were evaluated as bat roosting habitat in 25 states at elevations from sea level to 10,000 feet. Field surveys were conducted at 2,421 highway structures. Scientific literature was reviewed, and local biologists and engineers were interviewed, leading to the discovery of approximately 4,250,000 bats of 24 species living in 211 highway structures. Only one percent of existing structures had ideal conditions for day roosting, but at little or no extra cost a much larger percentage could provide habitat for bats in the future. Most species chose concrete crevices that were sealed at the top, at least 6 to 12 inches deep, 0.5 to 1.25 inches wide, and 10 feet or more above ground, typically not located over busy roadways. Retrofitting existing bridges and culverts proved highly successful in attracting bats, especially where bats were already using them at night. Providing bat habitat in bridges or culverts, either during initial construction or through subsequent retrofitting, is an exceptionally feasible and popular means of mitigation that is highly cost-effective in demonstrating a proactive commitment to the environment. Advice for incorporating bat roosts, both before and after construction, is provided. Environmental and economic benefits, impacts on structural integrity and public safety, and management of occupied structures are discussed.

  • Record URL:
  • Corporate Authors:

    Bat Conservation International, Incorporated

    P.O. Box 162603
    Austin, TX  United States  78716

    Texas Department of Transportation

    Greer Highway Building, 125 East 11th Street
    Austin, TX  United States  78701-2483

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Keeley, Brian W
    • Tuttle, Merlin D
  • Publication Date: 1999


  • English

Media Info

  • Media Type: Digital/other
  • Features: Appendices; Figures; Maps; Photos; References;
  • Pagination: 40p

Subject/Index Terms

Filing Info

  • Accession Number: 01670160
  • Record Type: Publication
  • Report/Paper Numbers: Resource Publication No. 4
  • Created Date: Apr 25 2018 10:39AM