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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations

This report is an archived publication and may contain dated technical, contact, and link information
Publication Number: FHWA-HRT-08-034
Date: August 2008

Wildlife-Vehicle Collision Reduction Study: Report To Congress

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Chapter 1. Introduction

In the recently enacted transportation bill, the Safe, Accountable, Flexible, and Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU Public Law 109-59), the U.S. Congress directed the Secretary of Transportation to conduct a national WVC study. In response, FHWA sponsored a WVC study aimed at reviewing methods to reduce collisions between motor vehicles and wildlife. The Study will advance the understanding of the causes and impacts of WVCs and identify solutions to this growing safety problem. This Study is a unique opportunity to synthesize current knowledge from the United States, Canada, Europe, and elsewhere to promote the expertise, coordination, and effectiveness of transportation agencies in addressing WVCs and, ultimately, reduce WVCs on U.S. roadways.

Approximately 300,000 reported collisions between cars and large animals (i.e., animals capable of causing substantial property damage upon impact) occur every year in the United States, and the number is steadily increasing. Including unreported collisions, the total number is more likely between one and two million WVCs annually. The increasing trend is expected to continue as both traffic volumes and deer populations continue to increase nationwide. Of the reported crashes, approximately 26,000 resulted in human injuries and 200 resulted in human fatalities per year. This study identified 21 federally listed threatened or endangered animal species in the United States for which road mortality was documented as a major threat to their survival.

The remainder of this report provides information relating to WVCs and associated mitigation measures based on the literature review. The primary sections are listed below:

  • Causes and Characteristics of WVCs provides an overview of what is known about WVCs. It includes those issues documented in the literature and provides an analysis of national crash datasets. This section is primarily focused on large animals.

  • Economic Impacts of Wildlife-Vehicle Collisions summarizes the known costs of WVCs nationally. This section is also primarily focused on large animals.

  • Impacts to Wildlife provides a list and discussion of endangered species that are known to be impacted by WVCs directly. This report does not include issues relating to habitat loss, habitat fragmentation, or other impacts of roadways on wildlife.

  • A broad range of Mitigation Methods are discussed in several sections (organized into major categories). For each mitigation method, the report provides, if available, (1) a general description, (2) case studies (with contacts), (3) benefits and drawbacks, (4) costs, and (5) design guidelines. The major mitigation categories considered are as follows:

    • Methods that aim to influence driver behavior.

    • Methods that aim to influence animal behavior with no or minimal structures on/over the road or in the right of way.

    • Methods that seek to reduce the wildlife population size.

    • Methods that aim to physically separate animals from the roadway.

    • Planning considerations.

  • Results are summarized for an Evaluation of Mitigation Methods by a Technical Working Group of national experts.

  • Gaps in Current Knowledge provides a summary of topics related to WVCs that require further research and investigation.

  • Cost-Benefit Analyses provides an overview of the costs and benefits of the different mitigations.

  • A brief Conclusion ends the report.

This document reports on Tasks 1–3 of the study, which include a literature review and technical working group meeting. Other elements of this project, which will be covered in later separate deliverables, include the following:

  • Best Management Practices Manual.

  • Training Course.

In this document three terms are used to describe collisions with animals. Animal-vehicle collisions (AVCs) refer to collisions with wild and domestic animals in cases where domestic animals could not be separated from the dataset. WVCs include all species of wild animals. Deer-vehicle collisions (DVCs) include WVCs that involve only deer (Odocoileus sp.). The reason a separate term is used for deer and no other specific type of animal is that deer account for a majority of WVCs when data are available. When information is specific to one type of animal other than deer, no abbreviation is used (e.g., moose-vehicle collision).

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