Synthesis of Animal-Vehicle Collision Mitigation Measures

              Synthesis of Animal- Vehicle Collision
Mitigation Measures
Final Report 612
Prepared by:
Courtney Reuer
HDR Engineering, Inc.
3200 East Camelback Road, Suite 350
Phoenix, AZ 85018
August 2007
Prepared for:
Arizona Department of Transportation
206 South 17th Avenue
Phoenix, AZ 85007
in cooperation with the
U. S. Department of Transportation
Federal Highway Administration
The contents of this report reflect the views of the authors who are responsible for the
facts and the accuracy of the data presented herein. The contents do not necessarily
reflect the official views or policies of the Arizona Department of Transportation or the
Federal Highway Administration. This report does not constitute a standard,
specification, or regulation. Trade or manufacturers' names which may appear herein are
cited only because they are considered essential to the objectives of the report. The U. S.
Government and the State of Arizona do not endorse products or manufacturers.
Technical Report Documentation Page
1. Report No.:
FHWA- AZ- 07- 612
2. Government Accession No. 3. Recipient’s Catalog No.
4. Title and Subtitle
Synthesis of Animal- Vehicle Mitigation Measures
5. Report Date:
August 2007
6. Performing Organization Code
7. Authors: Courtney Reuer 8. Performing Organization Report No.
9. Performing Organization Name and Address
HDR Engineering, Inc.
3200 East Camelback Road, Suite 350
Phoenix, AZ 85018
10. Work Unit No.
11. Contract or Grant No.
SPR- PL- 1-( 67) 612
12. Sponsoring Agency Name and Address
Arizona Department of Transportation
206 South 17th Avenue
Phoenix, AZ 85007
13. Type of Report & Period Covered
Final Report
14. Sponsoring Agency Code
15. Supplementary Notes:
Prepared in cooperation with the U. S. Department of Transportation, Federal Highway
Administration
16. Abstract
In all western states, domestic animal and wildlife populations are increasing as well as the
vehicular traffic volumes. Consequently, increases in animal- vehicle collisions have been
reported by many states. The purpose of this report is to provide a synthesis of animal-vehicle
collision mitigation measures utilized by other states and to provide a cost- effective
recommendation for ADOT to further reduce animal- vehicle collisions. Preparation for this
report included assembling documented studies currently underway and existing reports, and
conducting a survey among selected states and countries to learn what practices have been
used for solving or alleviating animal- vehicle collisions.
17. Key Words
Cattle guard, elk fencing, right of way
fencing, animal crossings, animal- vehicle
collisions
18. Distribution Statement
Document is available to the
U. S. public through the
National Technical
Information Service,
Springfield, Virginia 22161
23. Registrant’s Seal
19. Security Classification
Unclassified
20. Security Classification
Unclassified
21. No. of Pages
24
22. Price
SI* ( MODERN METRIC) CONVERSION FACTORS
APPROXIMATE CONVERSIONS TO SI UNITS APPROXIMATE CONVERSIONS FROM SI UNITS
Symbol When You Know Multiply By To Find Symbol Symbol When You Know Multiply By To Find Symbol
LENGTH LENGTH
in inches 25.4 millimeters mm mm millimeters 0.039 inches in
ft feet 0.305 meters m m meters 3.28 feet ft
yd yards 0.914 meters m m meters 1.09 yards yd
mi miles 1.61 kilometers km km kilometers 0.621 miles mi
AREA AREA
in2 square inches 645.2 square millimeters mm2 mm2 Square millimeters 0.0016 square inches in2
ft2 square feet 0.093 square meters m2 m2 Square meters 10.764 square feet ft2
yd2 square yards 0.836 square meters m2 m2 Square meters 1.195 square yards yd2
ac acres 0.405 hectares ha ha hectares 2.47 acres ac
mi2 square miles 2.59 square kilometers km2 km2 Square kilometers 0.386 square miles mi2
VOLUME VOLUME
fl oz fluid ounces 29.57 milliliters mL mL milliliters 0.034 fluid ounces fl oz
gal gallons 3.785 liters L L liters 0.264 gallons gal
ft3 cubic feet 0.028 cubic meters m3 m3 Cubic meters 35.315 cubic feet ft3
yd3 cubic yards 0.765 cubic meters m3 m3 Cubic meters 1.308 cubic yards yd3
NOTE: Volumes greater than 1000L shall be shown in m3.
MASS MASS
oz ounces 28.35 grams g g grams 0.035 ounces oz
lb pounds 0.454 kilograms kg kg kilograms 2.205 pounds lb
T short tons ( 2000lb) 0.907 megagrams
( or “ metric ton”)
mg
( or “ t”)
mg megagrams
( or “ metric ton”)
1.102 short tons ( 2000lb) T
TEMPERATURE ( exact) TEMPERATURE ( exact)
º F Fahrenheit
temperature
5( F- 32)/ 9
or ( F- 32)/ 1.8
Celsius temperature º C º C Celsius temperature 1.8C + 32 Fahrenheit
temperature
º F
ILLUMINATION ILLUMINATION
fc foot candles 10.76 lux lx lx lux 0.0929 foot- candles fc
fl foot- Lamberts 3.426 candela/ m2 cd/ m2 cd/ m2 candela/ m2 0.2919 foot- Lamberts fl
FORCE AND PRESSURE OR STRESS FORCE AND PRESSURE OR STRESS
lbf poundforce 4.45 newtons N N newtons 0.225 poundforce lbf
lbf/ in2 poundforce per
square inch
6.89 kilopascals kPa kPa kilopascals 0.145 poundforce per
square inch
lbf/ in2
SI is the symbol for the International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380
Table of Contents
1.0 INTRODUCTION ................................................................................................. 1
2.0 BACKGROUND.................................................................................................... 2
2.1 Animal Behavior................................................................................................. 3
2.1.1 Livestock..................................................................................................... 3
2.1.2 Wildlife ....................................................................................................... 3
2.2 Arizona’s Current Practices and Studies............................................................. 3
2.2.1 ADOT’s Design Guidelines and Standards ................................................ 3
2.2.2 ADOT’s Existing Studies ........................................................................... 5
3.0 OPPORTUNITIES ................................................................................................ 7
3.1 Interagency Coordination.................................................................................... 8
3.2 Public Education ................................................................................................. 8
3.3 Solutions to Alleviate Animal- Vehicle Collisions.............................................. 9
3.3.1 Cattle Guard................................................................................................ 9
3.3.2 Fencing........................................................................................................ 9
3.3.3 Construction.............................................................................................. 10
3.3.4 Post Construction and Maintenance.......................................................... 11
3.3.5 Driver Awareness...................................................................................... 11
3.3.6 Infrastructure Adaptation .......................................................................... 12
3.3.7 Animal Deterrent ...................................................................................... 13
3.3.8 Vehicle Systems........................................................................................ 13
4.0 RECOMMENDATIONS .................................................................................... 15
5.0 WEBSITES........................................................................................................... 16
6.0 BIBLIOGRAPHY................................................................................................ 17
List of Acronyms
ADOT Arizona Department of Transportation
ATRC Arizona Transportation Research Center
BCMoT British Columbia Ministry of Transportation and Infrastructure
BLM Bureau of Land Management
DOT Department of Transportation
FHWA Federal Highway Administration
GIS Geographic Information System
ICOET International Conference on Ecology & Transportation
ROW Right of Way
USDA United States Department of Agriculture
USDOT United States Department of Transportation
1
1.0 INTRODUCTION
Animal- vehicle collisions in Arizona have a large effect on highway safety and the local
economy. Due to growth in wildlife and vehicular traffic throughout Arizona, the
number of animal- vehicle collisions has a potential to increase. Accidents involving
wildlife can result in significant damage to transport trucks and other motor vehicles and
produce long traffic delays. This is especially true in remote areas where alternative
highway routes are not readily available ( Sielecki 2005). The Arizona Department of
Transportation ( ADOT) is currently studying various measures to reduce animal- vehicle
collisions.
Each year more than 200 motorists are killed and 29,000 more are injured in animal-vehicle
collisions in the United States ( Bies 2007). The insurance industry estimates the
annual cost to society for these fatalities and injuries is $ 200 million. The nationwide
average for vehicle repair costs incurred from animal- vehicle collisions is approximately
$ 2,000. With continued urban sprawl and suburban development the costs associated
with animal- vehicle collisions is likely to increase ( Peterson et al. 2003).
The purpose of this report is to provide a synthesis of animal- vehicle collision mitigation
measures utilized by other states and agencies and to provide a cost- effective
recommendation for ADOT to further reduce animal- vehicle collisions. Preparation for
this report included documenting studies currently underway and existing reports, and
conducting a survey among selected states and countries to learn what practices have
been used for solving or alleviating animal- vehicle collisions.
2
2.0 BACKGROUND
In 2005, Arizona had an estimated population of 6,044,985, which is an increase of
17.8% from the year 2000 census ( Arizona Workforce Informer 2007). This population
increase has led to an increase in vehicular traffic and may potentially add to the number
of animal- vehicle collisions throughout Arizona causing both economic and highway
safety concerns. While the number of households in the U. S. grew by 72% between 1969
and 2001, household vehicle miles traveled shot up by 193% ( Oberstar 2005).
ADOT has actively taken actions and measures to reduce animal- vehicle collisions. For
example, a research report titled Evaluation of Measures to Minimize Wildlife- Vehicle
Collisions and Maintain Permeability across Highways: Arizona Route 260 ( Dodd et al.
2007) reports the results of a study conducted on ways to minimize the incidence of
wildlife- vehicle collisions along Arizona State Route 260.
In all western states, elk populations and vehicular traffic volumes are increasing.
Consequently, increases in elk- vehicle collisions have been reported by many states. The
reported number of elk- vehicle collisions in 2003 in Arizona was 396. However, it is
estimated that the actual number of elk killed in highways may be two to three times that
reported ( Ruediger et al. 2005). Arizona’s efforts in studying wildlife habitat
fragmentation due to highway systems and possible solutions will go a long way in
reducing animal- vehicle collisions statewide.
A number of states in the United States have also taken a leadership role in addressing
wildlife ecology and transportation through policy, procedure, planning, project
development, design, construction, and maintenance. However, these states vary in the
treatment of animal- vehicle collisions due to lack of national uniform standards and
guidelines for mitigation. The International Conference on Ecology and Transportation
( ICOET) has demonstrated that some European countries are ahead of the United States
in this area of science and research ( Bank et al. 2002).
Animal- vehicle collision mitigation studies and measures fall into two categories: those
for wildlife and those for domestic animals or livestock. In 2003, deer were struck in
three out of four animal- vehicle collisions that caused human fatalities, but collisions
with other animals such as cattle, horses, dogs and bears also led to fatalities ( Huijser et
al. 2007). The average adult elk weighs 600- 850 pounds. This indicates that an elk-vehicle
collision has the potential to be much more serious than a deer- vehicle collision
( Ruediger et al. 2005). The traditional high and strong fencing and cattle guards have
proven to work for some animals, but there are new measures that have been proposed
and studied throughout the world to mitigate the number of animal- vehicle collisions on
highways. Recent studies include how to cost- effectively apply various fencing material
to different locations.
3
2.1 Animal Behavior
Understanding livestock and wildlife behavior is necessary before designing and
implementing an effective animal exclusion method.
2.1.1 Livestock
Cattle, horses, and mules have panoramic vision: they can see everything except what is
directly behind them. Cattle also have very limited depth perception. While a cow may
see a fence nearby, it cannot judge its distance. Livestock, especially cattle, are curious
creatures that often investigate fence oddities and use stationary structures to rub against
( AgrAbility Project 2002). Often cattle rub against fencing poles causing damage to
fencing and creating gaps for cattle to wander onto adjacent property or highway right- of-ways,
creating the potential for animal- vehicle collisions.
2.1.2 Wildlife
Wildlife behavior is related to the " fight- or- flight response.” Wildlife feel safe when there
is space or a boundary around them. Once that boundary is violated the animal’s
response is unpredictable. Even if an animal sees a vehicle, it may still jump in front of
it, or it may not even recognize the vehicle as a danger and may bolt in front of it, greatly
increasing the chance of a collision. Wildlife also tend to travel in groups and if one
animal crosses the road, there may be others that follow.
Humans may see roads as being a dangerous place for animals, but wildlife is attracted to
the road, highway right- of- way, and roadside ditches, for many reasons including:
• Grasses growing within the highway right- of- way can increase feeding.
• Removal of snow in the winter can provide for ease of movement.
• More wind on the road and right- of- way provides relief from biting insects.
• Product spillage ( such as grain) from vehicles can create temporary food sources.
( Wildlife Collision Prevention Program 2007)
2.2 Arizona’s Current Practices and Studies
ADOT has actively taken measures to reduce both domestic and wildlife animal- vehicle
collisions through policies, guidelines, and research.
2.2.1 ADOT’s Design Guidelines and Standards
The ADOT Roadway Design Manual ( ADOT 2007a) and the Construction Standard
Drawings ( ADOT 2007b) provide standardized preparation and implementation
procedures for highway design and construction throughout Arizona. Specific guidelines
and drawings have been developed for right- of- way fencing and cattle guards to keep
domestic animals from entering the right- of- way and interfering with traffic.
4
Roadway Design Manual
Sections 313 and 314 of the Roadway Design Manual are ADOT’s guidelines for right-of-
way fencing and cattle guards.
313 – Right- of- Way Fence
Fencing is provided along the ADOT right- of- way to physically identify the right-of-
way and to impede unauthorized access onto the right- of- way.
All controlled access highways shall have right- of- way fencing except where
walls or other physical barriers adequately define the right- of- way or where
public access to the highway is permitted.
Non- controlled access highways in rural areas should be fenced. In fringe- urban
areas, highways should be fenced unless access to adjacent properties is so
frequent that only short runs of fencing could be provided.
In urban areas, those state highways which also function as arterial streets
generally should not be fenced since access to the adjacent properties may be
expected to be provided at frequent intervals along the highway.
The construction standard drawings include the standard types of fences generally
used by ADOT. The types of fencing to be included in the plans depends upon a
number of factors and the selection should involve representatives from the
ADOT district, the right- of- way group, and the environmental planning and
enhancement group.
314.1 – Cattle Guards
Cattle guards, with or without gates, may be required to prevent livestock from
interfering with roadway traffic or to maintain range control. To prevent cattle
from entering the right- of- way, the construction of cattle guards may be required
at side roads and private entrances. When placed near traffic interchanges on a
crossroad, cattle guards without gates should be placed at or near the access
control line to prevent livestock entering the main roadway. Only under unusual
circumstances will cattle guards be justified in urban areas. The number of units
required should be determined by the width of the roadway.
Construction Standard Drawings
The following are ADOT’s construction standard drawings for cattle guards and fencing.
C- 11.10 Roadway Cattle Guard ( 3 Sheets)
C- 11.20 Cattle Guard, Drainage
C- 12.10 Fence Woven Wire with Gates ( 5 Sheets)
C- 12.20 Fence, Chain Link Types 1 and 2 with Gates ( 3 Sheets)
C- 12.30 Fence, Chain Link Cable Barrier ( 3 Sheets)
ADOT’s construction standard drawings for cattle guards and fencing are very similar to
other states. ADOT doesn’t, however, have a standard detail for wildlife fencing. Due to
5
the size and agility of wildlife, wildlife fencing must be higher and more specialized than
typical right- of- way fencing used to contain livestock. Wildlife exclusion systems should
be designed for specific species that represent the greatest potential hazard to the
motoring public. The structural components of the fencing should be designed to
withstand the forces of the largest animals and prevent the smallest animals from
breaching gaps in the fence ( Sielecki 2005). ADOT is currently testing several types of
wildlife fencing. Standards will be considered upon conclusion of various wildlife-vehicle
crash studies.
The British Columbia Ministry of Transportation and Infrastructure ( BCMoT) has found
exclusion fencing to be the most effective means of keeping wildlife off highway right-of-
ways. BCMoT’s experience with 2.4m ( 8 feet) high fencing on both sides of right- of-way
show it is 97% - 99% effective in preventing wildlife- vehicle accidents ( Sielecki
2004). The bottom of the fence may need to be buried to prevent bears and coyotes from
digging under the fence and providing access to the highway for other animals ( Ruediger
et al. 2005).
2.2.2 ADOT’s Existing Studies
State Route 260
In a coordinated effort among ADOT, FHWA, the US Forest Service and the Arizona
Game and Fish Department, new highway upgrades were implemented to Arizona State
Route 260 that addressed traffic and safety concerns. A major goal of this plan is to
improve wildlife protection and habitat connectivity in the area. Habitat fragmentation
associated with highways and other developments can affect wildlife populations by
reducing or eliminating access to important habitat components ranging from critical
winter range to key watering sites.
ADOT has employed a comprehensive package of mitigation measures along SR 260.
These measures include eleven sets of bridged wildlife underpasses, six sets of larger
bridges over streams, wildlife- proof fencing, innovative fencing alternatives, such as
steep cut- and- fill slopes and " elk rock" or closely placed rock rip- rap, to deter movement
across the highway and encourage use of underpass structures, and escape structures to
prevent wildlife from getting trapped within the fenced roadway sections.
Once completed, the SR 260 project will be one of the most comprehensive efforts in
North America to reduce the risk of wildlife- vehicle collisions and maintain or enhance
wildlife passage across a highway corridor. Current and future research, including a full
analysis of the relationship between wildlife passage and design characteristics of all
seventeen sets of underpasses and other project features such as fencing and escape
structures should contribute substantially to the understanding of wildlife and highway
relationships. For more information on SR 260 mitigation measures, see Evaluation of
Measures to Minimize Wildlife Vehicle- Collisions and Maintain Wildlife Permeability
Across Highways: Arizona Route 260 ( Dodd et al. 2007).
6
US 93
The realignment of U. S. Highway 93 in Arizona and Nevada, entitled the Hoover Dam
Bypass Project, includes the construction of 3.5 miles of new roadway and a bridge
across the Colorado River. The Arizona Game and Fish Department, with funding from
FHWA and ADOT, placed collars on thirty bighorn sheep to study their migration
patterns. The realignment of U. S. Highway 93 has been designed to mitigate impacts on
bighorn habitat by including wildlife crossings, jump- outs and fencing. The corridor
study of impacts of construction and mitigation measures on desert bighorn sheep are
ongoing.
7
3.0 OPPORTUNITIES
Reducing the risk of collisions between motor vehicles and animals will mean fewer
human injuries and fatalities, less money spent on vehicle repair and insurance costs, and
reduced mortality in wildlife and livestock populations. In addition, allowing safe passage
for wildlife will also ensure that animals have access to all necessary habitats and resources
and that connectivity among different populations is maintained ( Lloyd and Alexis 2005).
Each highway project needs to be evaluated individually because not all mitigation
measures will have the same set of factors including project location, area habitat, and
roadway design. When wildlife is considered during the planning process for roadway
design the overall cost will be minimized. Designers and agencies should work with the
entities that manage landscapes surrounding project areas to minimize animal crossings
and maintain the landscape structure cues that bring animals to mitigated crossing
locations ( Barnum 2003). ADOT’s animal exclusion solutions should meet these five
goals to be considered effective:
1. Improve public safety
2. Reduce animal mortality
3. Maintain wildlife habitat and connectivity
4. Protect threatened populations of wildlife species
5. Be cost- effective
Developing a comprehensive and efficient strategy for addressing the environmental,
economic, and social costs of animal- vehicle collisions must therefore be based on an
understanding of where conflicts between wildlife and highway operations are most
severe ( Lloyd and Alexis 2005). Having identified the scope of the problem and location
of the accident hotspots regarding animal- vehicle collisions, more efficient decision
making can be developed into solution options and thereby more efficiently use the
limited economic resources ( Perrin and Disegni 2003). Obtaining crash data from
Arizona’s traffic records will help to identify problem areas of high animal- vehicle
collisions. Determining areas with high concentrations of animal- vehicle collisions can
be used in project prioritization for new highways and improvements or retrofits to
existing highways. Developing site specific solutions for these problem areas first will
create the best cost/ benefit ratio. BCMoT uses collision data to provide a detailed
historical record of wildlife mortality that is used as a tool for supporting decision-making
with regard to the development of wildlife exclusion systems on existing and
planned highways ( Sielecki 2005).
The use of GIS data by layering state highway systems, structure locations, wildlife
habitats, animal- vehicle collision data, land ownership, and livestock operations will
assist in determining the appropriate, habitat specific solutions for differing locations.
Arizona’s Wildlife Linkages working group has already developed and is currently
refining the statewide linkage map ( ADOT 2004). The GIS data will be used to identify
migration patterns and animal behavior. Broad- scale or landscape- level wildlife habitat
linkage analysis is critical to improving highway mitigation for wildlife ( Ruediger et al.
2005).
8
3.1 Interagency Coordination
Interagency education, coordination and cross training is an essential and cost- effective
method of communicating current efforts, problem areas and possible solutions for
animal- vehicle collisions. The streamlining, context- sensitive design, and stewardship
programs in state transportation agencies should be used to collaborate and share
information ( Bank et al. 2002). A common language is also needed for agencies to
communicate effectively and efficiently. The U. S. Forest Service has developed a
Wildlife Crossings Toolkit with a glossary of common terms used by engineers and
biologists on highway issues ( USDA 2007).
Europe has devised a communication network that has been developed to coordinate
information, enhance wildlife connectivity, and garner support for providing measures of
wildlife in the transportation system. The Europeans have used many symposia and
journals to spread information related to wildlife and transportation ( Bank et al. 2002).
Conducted every two years, the International Conference on Ecology & Transportation is
designed to address the broad range of ecological issues related to surface transportation
development, providing the most current research information and best practices in the
areas of wildlife, fisheries, wetlands, water quality, overall ecosystems management, and
related policy issues. The mission of the International Conference on Ecology and
Transportation is to identify and share quality research applications and best management
practices that address wildlife, habitat, and ecosystem issues related to the delivery of
surface transportation systems.
3.2 Public Education
Educating the public on issues concerning animal- vehicle collisions will go a long way in
reducing the number of collisions and improving highway safety for both the public and
wildlife. Increasing public awareness through education can be accomplished by a
variety of methods with relatively minimal cost. These methods include, but are not
limited to, specific project public involvement or outreach, driver education, public
service announcements, and an increase in media exposure.
Colorado has an ongoing education campaign called Colorado Wildlife on the Move. It is
an effort by state and federal agencies, insurance groups and non- profit organizations to
prevent traffic crashes involving wildlife. The educational effort includes the distribution
of more than 58,000 Driver Safety Tip Sheets at 175 locations in 85 cities across
Colorado, with a list of suggestions about how to avoid hitting animals. The most
important tip was a reminder to drivers to stay alert and slow down ( Southern Rockies
Ecosystem Project 2006).
Public involvement during the project planning phase is a great tool for educating the
public regarding the importance of highway safety using animal exclusion design
measures. The importance of public involvement in the planning process is evident on a
highway project in Slovenia where a public opinion survey and public demonstration
9
resulted in the placement of an underpass on the Ljubljana- Postonjana Highway for
wildlife/ human connectivity and hydraulic needs ( Bank et al. 2002). The public must
first understand the issue or problem before it can make a good judgment on a solution.
3.3 Solutions to Alleviate Animal- Vehicle Collisions
3.3.1 Cattle Guard
Cattle Guards – The basic objective of a cattle guard is to allow the rancher to pass
through a fenced livestock area without having to open and close a traditional gate, while
simultaneously keeping the livestock from passing through. Cattle guards also known as
deer guards, have been proven extremely effective in containing livestock when properly
installed and maintained. Since livestock lack depth perception they will not cross open
slatted construction. Painted white strips on black pavement have also been known to
contain cattle. Cattle guards require side framing for stability. Typical cattle guards are
6 to 8 feet across and 10 to 16 feet wide over a 2 foot deep pit. Maintenance is required
to remove debris accumulated in the pit.
If cattle guards are only required for a short period of time, temporary cattle guard may
be used. Temporary cattle guards are a raised platform with slats allowing vehicles to
cross, but not livestock.
Cattle guards are widely used to stop deer from crossing as well as cattle. Many cattle
guards have been installed at BLM and Forest Service sites throughout the Pacific North-west.
Both the Forest Service and BLM believe that the cattle guards have performed
beyond expectations, at reasonable cost, with minimal maintenance ( Vachowski 1998).
Cattle guards reduce deer crossings by at least 95% ( Curtis and Sullivan 2001). A study
to review deer control devices intended for use on airports concluded that deer would
approach cattle guards but rarely attempted to cross them ( Seamans 2001). However, in
snow country, cattle guards alone may not be as effective from deterring elk and other
wildlife from accessing the roadway because snow compaction in cattle guards allows
animals to walk across them and into the roadway ( Ruediger et al. 2005).
3.3.2 Fencing
Fencing along highway right- of- way is greatly effective in reducing animal- vehicle
collisions when it is designed to withstand the largest animal of concern within the area
of installation, is properly maintained and frequently inspected. Animal exclusion
fencing must be designed for different kinds of affected species. Wildlife exclusion
fencing is different than domestic animal ( livestock) exclusion fencing.
BCMoT wildlife exclusion fencing specifications are designed to produce a fence with a
15 to 20- year lifespan. Certain locations of wildlife exclusion fencing make daily
inspection and maintenance impractical. Wildlife exclusion fencing has proven very
effective in reducing wildlife accidents on the Coquihala Highway located between Hope
and Marritt in British Columbia, reducing wildlife accidents by 100% ( Sielecki 2005).
10
Fencing for elk and other ungulates should be at least 8 feet tall and used in conjunction
with overpasses and underpasses to improve effectiveness. Fencing commonly increases
elk use of underpasses or overpasses by 80% or more ( Ruediger et al. 2005).
British Columbia has established a Highways Fencing Program to increase motorist and
livestock safety. For land owners to be eligible for fence replacement they must operate
an active livestock operation adjacent to a highway right- of- way and the fencing must be
part of a complete containment system. Fence replacement priorities are given to areas in
most need or repair or reconstruction ( British Columbia Cattlemen’s Association 2007).
Fences are used extensively in the United Sates and Europe to keep wildlife off major
highways ( Bank et al. 2002). A variety of fence types are used. Fencing should be
designed to withstand the largest animal of concern within the area of installation.
British Colum- bia standard wildlife fencing is 8 feet tall and made of steel or wood posts
and wire mesh.
Fencing, combined with underpasses and overpasses as appropriate, is the only broadly
accepted method that is theoretically sound and proven to be effective in the reduction of
animal- vehicle collisions ( Hedlund et al. 2004). Fencing, intercept feeding, and eco-passes
are the most promising techniques currently available for reducing deer- vehicle
collisions. ( Romin and Bissonette 1996).
Fencing can become a trap if not adequately installed or maintained, increasing the
probability of an animal being struck by a vehicle. Animals caught within highway right-of-
way fencing can become stressed by both traffic and the inability to escape which
could result in an animal- vehicle collision ( Maine Interagency Work Group 2001). Fence
exits from the inside of highway right- of- way, one- way gates, earthen ramps, or funnel
fences should be provided to allow wildlife to return to their habitat. Many types of wild-life
one- way gates exist. Jump- outs or earthen ramps are a relatively new technology.
Their effectiveness is being studied on the new alignment of U. S. Highway 93 in Arizona
and Nevada. Because the roadway has not been opened to vehicular traffic, no conclu-sions
as to their effectiveness have been determined. Wildlife tends to follow fencing
until they find gaps to traverse. Funnel fencing leads wildlife to strategically placed one-way
gates.
Roadway geometry plays a large role in determining necessary placement of animal
exclusion fencing. If animal at- grade crossings are necessary, they should be located on
the designed roadway tangent where driver’s line- of- sight is maximized providing
motorists adequate time to react if an animal is crossing the highway. For low- volume
highways where animal- vehicle collisions do not present a significant safety hazard to
animals or drivers, the most cost- and biologically- effective strategy for reducing
conflicts is to encourage animals to cross freely at- grade.
3.3.3 Construction
Workmanship and materials are vital components of the construction phase for animal
exclusion systems. Attention to design by workers and the use of good quality materials
11
help ensure the systems will operate as designed for an extended period of time ( Sielecki
2005). It is important to construct animal exclusion systems using quality workmanship
and materials because continuous maintenance is difficult and costly to perform.
Wildlife exclusion systems are most easily incorporated into the design and construction of
new highways. In this way, the designs of major structures, such as bridges and culverts,
can be modified to maximize their effectiveness for wildlife passage ( Sielecki 2005).
3.3.4 Post Construction and Maintenance
Regular maintenance is essential for ensuring that fencing and cattle guards operate
properly. Fencing must be continually maintained because it can be easily damaged by
weather, erosion, animals and vehicles. Fencing with gaps due to erosion or topographic
contours can be traversed by deer and other wildlife. Maintenance of fencing must be
frequent in order to be successful in reducing animal- vehicle collisions because animals
exploit breaks in the fence ( Foster and Humphrey 1995).
Maintenance of cattle guards can be performed less frequently than fencing. If the cattle
guard is too short, lacks side guards or wings, or has incorrect spacing between the tread
rails, cattle may be tempted to try to jump or walk through it ( Vachowski 1998).
3.3.5 Driver Awareness
Road Lighting – According to FHWA road lighting is not effective in reducing wildlife
mortality. It does however increase driver awareness, but unless utilities exist near the
highway, the cost of implementing this solution is high.
Driver Education – As mentioned in 3.2.1 public education is a relatively inexpensive yet
extremely effective way to reduce animal- vehicle collisions.
Animal Detection Devices – Detection systems use radio frequencies and infrared sensors
to detect the presence of large animals. The system warns drivers as they are entering an
area of the freeway that there is an animal present ( Transport Canada 2003).
Reduction in speed limits – Reducing speed limits in areas with potentially high levels of
animal- vehicle collisions is effective in reducing collisions ( Maine Interagency Work
Group 2001). Reduced speeds provide motorists additional time to respond and are a
very low- cost solution. Colorado DOT has experimented with night time speed limit
reductions in areas with high wildlife activity crossing the roads. This research is
ongoing and additional data is needed before a determination can be made as to its
effectiveness.
Signing – Sixty percent of drivers will not notice wildlife crossing signage ( Perrin and
Disegni 2003). Highway signs tend to be so common, often for such long stretches of
road, that drivers become complacent to their warnings unless the warning on the sign is
reinforced by actual experience and drivers see wildlife in the area ( Danielson and
12
Hubbard 1998). According to Leonard Sielecki, an environmental issues analyst with
BCMoT, animal crossing warning signs decline in effectiveness over time. Combining
wildlife signs with speed limit signs seems to increase their effectiveness. Including
flashing lights also is believed to be effective ( Bank et al. 2002).
Thermal Sensors – Solar powered thermal sensors detect the presence of animals, which
triggers a fiberoptic wildlife warning sign to reduce the speed limit. This installation has
reduced wildlife mortality on a two- lane regional road in Switzerland ( Bank et al. 2002).
3.3.6 Infrastructure Adaptation
At- grade crossings – At- grade crossings for livestock and wildlife, combined with active
signs, offer a long- shot chance at providing greater safety than uncontrolled crossings
marked only with passive signs. At- grade crossings are most promising for highways that
cross mule deer migration routes in western states ( Hedlund et al. 2004). At- grade
crossings should only be implemented where traffic volumes are low ( Barnum 2003). The
Colorado Department of Transportation has a research project underway titled Roads and
Connectivity in Colorado: Animal- Vehicle Collisions, Wildlife Mitigation Structures, and
Lynx- Roadway Interactions which focuses on a means to maintain an at- grade crossing for
wildlife. The research is focusing on a detection system using electromagnetic detection to
identify when animals are moving within the right- of- way towards the road. The detection
will be used to activate lighting at night to illuminate the roadside for drivers to see the
animals more easily. This research is scheduled to be completed in 2008 but may take
several years to provide conclusive evidence to validate this type of mitigation.
Cattle Underpasses – Cattle underpasses are used in British Columbia in conjunction
with fencing and cattle guards and have proven effective when regular fence maintenance
is performed.
Deer Crosswalk - Crosswalks are used in conjunction with fencing to funnel deer to
specific crossing locations. Deer crosswalks are dirt paths that run from one- way gates in
highway fencing across dirt portions of the right- of- way. Paint is used to delineate
crosswalks on the actual roadway surface. Stone river cobble, which is believed to deter
deer from leaving the path, is placed along both sides of the dirt path. Complete
elimination of deer- vehicle collisions is unlikely with the use of the crosswalk technique.
However, they are a lower- cost alternative to overpasses and underpasses ( Danielson and
Hubbard 1998).
Clearing right- of- way – Roadside clearing may be effective, although there is very
limited information supporting it. Roadside clearing must be part of a broader strategy of
roadway design and maintenance ( Hedlund et al. 2004).
Wildlife Underpasses – Wildlife underpasses are structures that provide grade separation
between motor vehicles and animal traffic. Underpasses increase the success of exclu-sion
fencing by increasing the permeability and habitat connectivity across highways.
There are many ongoing studies on Arizona’s State Route 260 to determine what type of
13
structures and different configurations of the seventeen wildlife underpasses constructed
are most used by wildlife. Effective underpasses for elk are the open- span crossings.
These are large bridges that have long roadway spans with sloped abutments to the
natural ground floor. Engineers and biologists in Canada and Arizona often recommend
open- span wildlife crossings as both effective and cost efficient ( Ruediger et al. 2005).
Wildlife Overpasses – Wildlife overpasses are sometimes considered green bridges and
can be straight or hourglass shaped. They are vegetated highway overpasses which
greatly improve habitat connectivity. Wildlife overpasses are costly and therefore should
only be placed where existing wildlife habitat exists and connectivity is desired.
Overpasses in Europe are considered successful for the largest spectrum of animals. The
presence of habitat on overpasses allows for use by everything from insects to large
carnivores. Structure size, width, location, and habitat must be considered in the design
of overpasses for the target species in the area of application. Overpasses can serve dual
purposes, where small volume roads or human recreational activities share the overpass
( Bank et al. 2002).
Culverts – A culvert is a conduit covered with embankment around the entire perimeter
and can be in the shape of a rectangle, circle or arch. Small animals can pass under an
intersecting roadway through a culvert. Culverts are most effective as animal crossings
when paired with fencing directing the animals away from the highway right- of- way.
3.3.7 Animal Deterrent
Reflective Devices – Reflectors are less expensive and less intrusive than fencing,
however, studies suggest that reflectors do not modify wildlife behavior and are therefore
ineffective ( Perrin and Disegni 2003).
Wildlife Warning System – Wildlife warning systems alert wildlife at an animal crossing
that a vehicle is approaching. Upon activation animals are frightened away from the
roadway allowing vehicles to pass safely ( Bushman et al. 2001). This system may cause
animals to run onto the road, and is only cost effective for small areas.
Animal Repellents – Deer repellents have a limited effect on modifying deer feeding and
movement patterns ( Hedlund et al. 2004). Animals adapt to the scent and therefore the
repellents are ineffective in alleviating animal- vehicle collisions.
3.3.8 Vehicle Systems
Vehicle Mounted Whistles - Research in the United States has indicated that deer whistles
and other ultrasonic devices are ineffective in reducing wildlife- vehicle accidents ( Curtis
and Sullivan 2001).
Night Vision - Night Vision is available as an option on all Cadillac’s DeVille 2000
models as well as some other makes/ models. Night Vision uses thermal imaging, or
infrared, technology to create pictures based on heat energy emitted by objects in the
14
viewed scene. Night Vision uses a refractive optical- lens system to gather infrared
energy. Infrared driver vision technology in vehicles may be effective in the future. Its
development and implementation will depend on its usefulness in improving driver night
vision ( Hedlund et al. 2004). This system is available on high- end vehicles only and
therefore is of limited use for the general driving public.
15
4.0 RECOMMENDATIONS
Based on the results of previous studies and reports, the following are recommended cost-effective
practices and measures for alleviating the animal- vehicle collisions throughout
Arizona.
• Start early – Begin thinking about wildlife and livestock issues and exclusion
solutions at the planning stages of design projects.
• Continue Arizona’s efforts of interagency coordination, education and cross
training for communicating current efforts, problem areas and possible solutions
for animal- vehicle collisions. Educate the design team through interagency
meetings on specific projects.
• Implement a public education program to increase public awareness. Educate the
public on specific projects through project outreach, including open houses, design
workshops, and community meetings.
• Determine areas of high animal- vehicle collisions through trend analysis of
collision data. Prioritize animal exclusion projects on existing highway systems
based on areas of high levels of animal- vehicle collisions. Study areas of high
animal vehicle collisions prior to any new roadway or bridge design.
• Design site- specific solutions of animal exclusion projects based on location, area
habitat, and roadway design.
• Continue refining GIS data to determine actual wildlife habitats in relation to the
Arizona state highway system. Using GIS data, avoid placing highways were
large habitats exist.
• Combine the use of animal exclusion fencing, cattle guards and underpasses for
maximum habitat continuity and reduction in animal- vehicle collisions.
• Maintain fences through inspections, especially in areas of livestock grazing or
known wildlife habitats.
16
5.0 WEBSITES
The following websites are useful in providing up- to- date material on animal- vehicle
collision mitigation measures and studies from around the world.
British Columbia Cattlemen’s Association – Highways Fencing Program
http:// www. cattlemen. bc. ca/ hwy_ fencing. htm
Center for Transportation and the Environment
http:// itre. ncsu. edu/ cte
FHWA – Critter Crossings – Linking Habitats and Reducing Road Kill
http:// www. fhwa. dot. gov//// environment/ wildlifecrossings
International Conference on Ecology and Transportation
http:// www. icoet. net
Wildlife Crossings Toolkit
http:// www. wildlifecrossings. info
Wildlife- Vehicle Accident Prevention Program
http:// www. wildlifeaccidents. ca/
17
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