Abstract
Annual vehicle miles driven in the United States doubled, from 1.6 trillion to 3.2 trillion in the 40 years between 1983 and 2023. Unfortunately, one side effect of the increase in vehicle miles driven has been the prevalence of Animal-Vehicle Collisions (AVCs).
As early as 1975, efforts began in some Western states to create safe animal passages such as the wildlife overpass over I-15 in Beaver, Utah. Wildlife passages increased in popularity from the 1970s through the 1990s, but they were mainly being designed and constructed in the Western United States.
Today, there is increasing and broader interest in safe wildlife passages across the United States with major coalitions forming in different areas to promote the adoption of wildlife passages for both animal and human safety. This study examines what other Midwestern states are doing regarding designing animal passages into new and reconstruction bridge projects.
In this area, Indiana is a leader in making accommodations for small wildlife passages as states such as Michigan and Tennessee have not yet incorporated wildlife crossing into their bridge design process. Ohio has integrated input from their Department of Natural Resources into its bridge design process, but it is not frequently used and the input is essentially only suggestion rather than requirement.
This study also examines the root cause of delays and increased costs on some INDOT bridge designs related to rework caused by not having timely input from DNR regarding wildlife crossings. This study has identified two key recommendations where making minor changes in INDOT’s New Project Development Process could ensure the timely flow of information to and from DNR to prevent late changes in bridge projects.
Keywords
wildlife crossing, animal crossings
Report Number
FHWA/IN/JTRP-2026/10
SPR Number
4922
Sponsoring Organization
Indiana Department of Transportation
Performing Organization
Joint Transportation Research Program
Publisher Place
West Lafayette, Indiana
Date of Version
2026
DOI
10.5703/1288284318618
Recommended Citation
Padfield, J., & Squillace, K. (2026). Identify bridge design guidelines for wildlife crossings (Joint Transportation Research Program Publication No. FHWA/IN/JTRP-2026/10). West Lafayette, IN: Purdue University. https://doi.org/10.5703/1288284318618
SPR-4922 Technical Summary