CONSTRUCTION GUIDELINES FOR WILDLIFE FENCING AND ASSOCIATED ESCAPE AND LATERAL ACCESS CONTROL MEASURES Requested by: American Association of State Highway and Transportation Officials (AASHTO) Standing Committee on the Environment Prepared by: Marcel P. Huijser, Angela V. Kociolek, Tiffany D.H. Allen, Patrick McGowen Western Transportation Institute – Montana State University PO Box 174250 Bozeman, MT 59717-4250 Patricia C. Cramer 264 E 100 North, Logan, Utah 84321 Marie Venner Lakewood, CO 80232 April 2015 The information contained in this report was prepared as part of NCHRP Project 25-25, Task 84, National Cooperative Highway Research Program, Transportation Research Board. SPECIAL NOTE: This report IS NOT an official publication of the National Cooperative Highway Research Program, Transportation Research Board, National Research Council, or The National Academies. Wildlife Fencing and Associated Measures Disclaimer DISCLAIMER DISCLAIMER STATEMENT The opinions and conclusions expressed or implied are those of the research agency that performed the research and are not necessarily those of the Transportation Research Board or its sponsors. The information contained in this document was taken directly from the submission of the author(s). This document is not a report of the Transportation Research Board or of the National Research Council. ACKNOWLEDGEMENTS This study was requested by the American Association of State Highway and Transportation Officials (AASHTO), and conducted as part of the National Cooperative Highway Research Program (NCHRP) Project 25-25 Task 84. The NCHRP is supported by annual voluntary contributions from the state Departments of Transportation. Project 25-25 is intended to fund quick response studies on behalf of the AASHTO Standing Committee on the Environment. The work was guided by a panel chaired by Todd Williams. Other panel members were Gail Anne D'Avino, Timothy Dexter, Norris Dodd, Jeff Gagnon, Todd Nichols, Kelly McAllister, Stirling Robertson, William C. Ruediger, and Leonard Sielecki, and Bill Ostrum was the FHWA liaison. The project was managed by Nanda Srinivasan and Crawford Jencks from NCHRP. Western Transportation Institute Page 2 Wildlife Fencing and Associated Measures Table of Contents TABLE OF CONTENTS 1. Introduction ............................................................................................................................15 1.1. Background .................................................................................................................... 15 1.2. Overview and Purpose of the Mitigation Measures Included in this Report ................. 16 1.3. Organization of the Report ............................................................................................. 17 2. Literature Review...................................................................................................................18 2.1. Organization of Literature Review ................................................................................. 18 2.2. Keep Wildlife Off the Road ........................................................................................... 18 2.2.1. Fence Location and Length ..................................................................................... 18 2.2.2. Where to Start, Where to Stop? .............................................................................. 19 2.2.3. Fence Material and Dimensions .............................................................................. 19 2.2.4. Fence End Treatments ............................................................................................. 23 2.2.5. Access Road Treatments ......................................................................................... 25 2.2.6. Effectiveness in Reducing Collisions ..................................................................... 26 2.2.7. Wildlife Mortality as a Result of Wildlife Crashing into Fences ........................... 27 2.2.8. Landscape Aesthetics .............................................................................................. 28 2.2.9. Costs ........................................................................................................................ 28 2.2.10. Maintenance ........................................................................................................ 29 2.3. Allow Wildlife to Escape the Fenced Road Corridor .................................................... 30 2.3.1. General Considerations ........................................................................................... 30 2.3.2. Passive One-Way Gates .......................................................................................... 31 2.3.3. Active One-Way Gates ........................................................................................... 31 2.3.4. Wildlife Jump-outs or Escape Ramps ..................................................................... 32 2.3.5. Branches Stacked Against Fence ............................................................................ 33 2.3.6. Lower Fences with Outrigger ................................................................................. 33 2.4. Warn Drivers and Traffic Calming in Fenced Road Corridor ....................................... 34 2.4.1. Warning signs ......................................................................................................... 34 2.4.2. Traffic Calming ....................................................................................................... 36 2.5. Allow Humans to Get In and Out of the Fenced Road Corridor .................................... 36 2.5.1. General .................................................................................................................... 36 2.5.2. Non-Motorized Use (Pedestrians, Bicyclists, Equestrian) ...................................... 36 2.5.3. Motorized Use ......................................................................................................... 38 3. Survey ....................................................................................................................................40 3.1. Organization of Survey .................................................................................................. 40 3.2. Methods .......................................................................................................................... 40 3.2.1. The Target Population............................................................................................. 40 3.2.2. Survey Development and Review ........................................................................... 41 3.3. Respondents ................................................................................................................... 42 3.4. Large and Medium-Sized Mammals .............................................................................. 46 3.4.1. Characteristics of the Respondents ......................................................................... 46 3.4.2. Measures to Keep Large and Medium-Sized Mammals Off the Road ................... 46 3.4.3. Allow Wildlife to Escape the Fenced Road Corridor ............................................. 55 3.4.4. Keep Wildlife Out of Fenced Road Corridor at Fence Gaps and Fence Ends ........ 59 3.4.5. Allow Humans to Get In and Out of the Fenced Road Corridor ............................ 64 3.4.6. At Grade Crossing Opportunities for Wildlife at Gaps or Fence Ends .................. 69 Western Transportation Institute Page 3 Wildlife Fencing and Associated Measures Table of Contents 3.5. Amphibians and Reptiles ............................................................................................... 76 3.5.1. Characteristics of the Respondents ......................................................................... 76 3.5.2. Measures to Keep Amphibians and Reptiles Off the Road .................................... 77 3.5.3. Allow Wildlife to Escape the Fenced Road Corridor ............................................. 85 3.5.4. Keep Wildlife Out Off Fenced Road Corridor at Fence Gaps and Fence Ends ..... 87 3.5.5. Allow Humans to Get In and Out of the Fenced Road Corridor ............................ 89 3.5.6. At Grade Crossing Opportunities for Wildlife at Gaps or Fence Ends .................. 93 3.6. Design Plans and Specifications .................................................................................... 96 3.6.1. Introduction ............................................................................................................. 96 3.6.2. Wire Mesh Fencing for Large Animals .................................................................. 97 3.6.3. Other Details ......................................................................................................... 112 3.6.4. Small Animals ....................................................................................................... 113 4. Cost-Benefit Analyses .........................................................................................................115 4.1. Introduction .................................................................................................................. 115 4.2. Methods ........................................................................................................................ 115 4.3. Results .......................................................................................................................... 118