Collisions between wildlife and vehicles cause many deaths
and injuries each year, and the economic cost of these collisions
is high. Recognizing this growing problem, highway maintenance
departments have good reason to investigate the effectiveness of
preventive measures.
The Insurance Institute for Highway Safety called roadside
wildlife reflectors "the most promising system for preventing
deer crashes." However, researchers who have studied the
effectiveness of roadside reflectors report conflicting findings.
WILDLIFE REFLECTORS NOT FOUND EFFECTIVE
California
A 1993 Federal Highway Administration report by S.G. Ford
and S.L. Villa indicated that California tested Swareflex
Wildlife Reflectors on a four-mile section of State Route 36 in
Plumas County. This section of highway was chosen for the
experiment because of its exceptionally high mule deer kill rate.
After three seasons of intermittent operation, deerkill
statistics showed no significant difference between times when
reflectors were in operation and times when they were not.
Colorado
In a 1991 Colorado Department of Transportation report, D.
Woodham wrote about the installation of Swareflex Reflectors near
Denver. For three months, two half-mile sections of reflectors
were alternately uncovered and covered. While no deer-vehicle
collisions happened in the test sections during the three months,
the experiment proved too expensive to continue. Researchers
mentioned the need for more investigation to find out how
effective reflectors are for mule deer and suggested a large-
scale, regional study using pooled funds and emphasizing valid
results.
Maine
James R. Gilbert described a Maine research project in a May
1982 report called "Evaluation of Deer Mirrors for Reducing Deer-
Vehicle Collisions." Between Topsham and Gardiner on newly
opened I-95, twelve random half-mile test sections were
established along almost fifteen miles of roadway. The research
took place from October 1977 through July 1981 and used Van de
Ree Mirrors (polished stainless steel squares with indentations
at each corner and one in the middle) in each test section,
leaving non-mirrored areas of at least a half-mile between test
sections. The number of deer killed was smaller than expected
and decreased markedly after the initial opening of the freeway.
Researchers conjectured deer became acclimatized to the new road
and remained on the highway for shorter periods, resulting in
fewer deerkills. Given the small sample and "the fact that more
deer were killed in the mirrored areas than the non-mirrored
areas," the researchers concluded "that the mirrors were probably
ineffective and anyway not justified in areas with so few deer-
vehicle accidents."
Gilbert offered a chronology of experiments conducted before
his 1982 report. He described the original test with Van de Ree
Reflectors. That test was in the Netherlands and compared
deerkill figures between 1958 and 1960, before reflectors were
installed, with figures between 1960 and 1962, after reflectors
were installed. Twenty deer were killed on the roadway when
there were no reflectors, and none were killed during the two
years after installation. Attempting to duplicate this apparent
success, subsequent studies using Van de Ree Reflectors took
place in Indiana, Colorado, and Michigan. All led to the
conclusion that the mirrors were not effective.
The original research on Swareflex Reflectors, according to
Gilbert, was conducted in Austria during the early 1970s.
Before-and-after figures for forty-two segments totaling 58 miles
of roadway and spanning from three to twenty-four months
"indicated a reduced kill." A subsequent test in Colorado failed
to find Swareflex Reflectors effective.
Gilbert criticized the design of many of the studies cited
above. He contended the size of the sample used in some
experiments was not large enough to represent statistically valid
evidence. Moreover, he pointed out:
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Very few of the studies have incorporated any statistical
design into their planning. Especially critical in
developing a project is to eliminate the effect of year to
year fluctuation in the number of deer crossing the right-
of-way. . . . Another problem which could arise is
comparing the numbers of deer killed at one time of year
(with no treatment) to those killed at another time of year
(with treatment). That deer activity and susceptibility to
vehicles varies with the time of year is well known.
Comparing Van de Ree mirrored reflectors with Swareflex's
prismatic system, John Strieter of Strieter Corporation
(exclusive U.S./Canadian importer and distributor of Swareflex
Reflectors) observed that the single flash of the mirrors
presents a different visual obstacle to deer than the traveling,
red beams of light reflected by the Swareflex devices. The
latter, according to Strieter, has proven more effective.
However, given the information from the Maine experiment
described above and from other studies of deer reflectors,
Gilbert finally concluded, "There is no statistically valid
evidence that either the Van de Ree stainless steel mirrors or
the red Swareflex Reflectors reduce vehicle-deer collisions."
Ontario, Canada
In a report for the Ontario Ministry of Transportation, J.J.
Armstrong described an installation of Swareflex Wildlife
Reflectors during the summer of 1990 on a two-lane section of a
highway in southern Ontario. For a year, crews covered and
uncovered the reflectors during alternate weeks and counted the
number of deer killed. Results showed the mirrors made no
significant difference. Individuals who observed deer behavior
when a vehicle passed claimed the animals seemed to react more to
the passing vehicle than to light patterns created by headlights
bouncing off the reflectors. Researchers concluded it would not
be cost-effective to use reflectors to reduce deer-vehicle
collisions on this section of Ontario roadway.
Washington State
In May 1992, Mary Ossinger wrote a report on a Washington
State deer-reflector study then in progress on Highway 101 near
Discovery Bay (northwestern Washington on the Olympic Peninsula).
Hoping to duplicate a successful test in Eastern Washington, for
three years the Washington Department of Transportation
alternately covered and uncovered reflectors installed in six
test sections. The test sections were in densely forested areas
inhabited by blacktail deer. Of nighttime deerkills, twenty
happened when the reflectors were active and twenty-one when they
were covered. Ossinger concluded, "Analysis of the test data
shows that the Swareflex Reflectors do not significantly reduce
deerkill in the Discovery Bay area."
Wyoming
Archie F. Reeve and Stanley H. Anderson called their report
on a Wyoming test of wildlife reflectors "Ineffectiveness of
Swareflex Reflectors at Reducing Deer-Vehicle Collisions." The
report appeared in a 1993 Wildlife Society Bulletin. Crews installed
reflectors on U.S. Highway 30 and alternately uncovered and
covered them for one-week and two-week periods for three years
(October 1986 through the summer of 1989). During the test
period "the observed number of deer killed when Swareflex
Reflectors were uncovered was greater than expected," leading
Reeve and Anderson to conclude, "Without asserting that Swareflex
Reflectors actually increased deer-vehicle collisions, they did
not diminish the problem on our study area." The authors cited
numerous inconclusive studies as further evidence that Swareflex
deer reflectors are ineffective. It is interesting to note the
report's assertion that "[t]he reflectors deteriorated during the
3-year study." The authors went on to explain that only 61
percent of the reflectors were functioning properly by the end of
the study. Apparently crews did not maintain the devices.
WILDLIFE REFLECTORS FOUND EFFECTIVE
British Columbia, Canada
In the Smithers area of British Columbia, Canadian highway
officials and the Canadian automobile insurance company shared
the cost of installing Swareflex Reflectors on highways and
railroad lines. John Young wrote about the project in The Interior
News, calling his article "Moose Reflectors Target Hot Spots."
In British Columbia, where moose-vehicle collisions are a major
problem, 6,411 wildlife-vehicle collisions in 1994 cost the
insurance company $11.3 million. According to Eric Becker, area
highway manager for Smithers, "Animal collisions dropped
dramatically in other areas of B.C. when reflectors were set up.
In all cases there's been a reduction."
Iowa
Reflectors were installed along a quarter-mile section of
Dubuque Street in Iowa City at a cost of $4,406 for reflectors
(including extras for replacement needs), materials, installation
labor, pruning labor, and equipment rental. In an area with a
high deerkill rate, the reflectors completely eliminated deer-
vehicle collisions during the first two months after
installation. According to her December 5, 1994 memo, Lisa C.
Goodman, Director of Animal Control for the Iowa City Police
Department, found the reflectors are "worth the money, when
public safety, public relations, animal safety and the costs
incurred by accidents, is taken into consideration."
G. I. Hoilien of Harpers Ferry wrote to Strieter
Corporation, distributor of the Swareflex Reflectors called
Strieter-Lite, to report, "After thirty years as an Iowa
Conservation Officer (Game Warden) in the business of protecting
wildlife, I've seen something 'Really Work'!" He explained that
he had documented about fifty deerkills, mostly at night, each
year on Highway 76 in the three years before the installation of
Swareflex Reflectors. Hoilien wrote, "After 7« years only 7 deer
have been reportedly killed in this area at night, which makes a
saving of 350-400 deer car accidents."
The conservation officer added personal testimony on the
effect reflectors have on deer and other wildlife. He explained:
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On patrol one night, I just entered the reflected area and
in my lights observed several deer running hard towards the
highway. When they neared the reflectors, it was as if they
had hit a fence. They skidded to a stop, turned and ran
back the way they had come. On other occasions, I've
observed fox and coyote with the same reaction.
Minnesota
Susan Mulvihill, Accident Surveillance/Safety Engineer for
the Minnesota Department of Transportation, reported on the
effectiveness of Swareflex Reflectors in a May 1990 letter to
John Strieter. For several sites where reflectors had been
installed, she estimated an overall deerkill rate reduction of 60
percent. While the reflectors reduced deer-vehicle collisions
wherever they were installed, the rate of reduction varied with
deer population, roadway traffic volumes, and number of roadway
miles in areas densely populated with deer.
The Tri-County River Bottom Bucks Chapter in Paynesville,
Minnesota purchased reflectors for use in that area. In a letter
from their secretary/treasurer, they reported a drop from 30 deer
killed per year to three and added:
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These Reflectors have been working better than expected.
We like to keep them replaced because we have learned that
if one is missing, it's like opening up a gate, and
roadkills occur there.
Oregon
From Rhododendron, Oregon, Michael P. Jones of The Wildlife
Fund wrote to Strieter Corporation in September of 1989. He
reported that installing Swareflex Reflectors on Highway 26 in
the Mount Hood corridor had resulted in a decrease in the number
of deer and other wildlife killed on the highway. Writing about
the effect of installing reflectors, Jones shared:
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No longer are we observing dead skunks, raccoons,
jackrabbits, porcupines, or opossums in or alongside the
highway. Swareflex is a "godsend" for wildlife. This
reflector system is one of the most important devices ever
designed to benefit our wildlife.
Washington State
A test of Swareflex Wildlife Reflectors on Highway 395 in
Eastern Washington near Spokane was the source of information in
a Washington Department of Transportation report dated August
1984. James A. Schafer, Stephen Penland, and William P. Carr
wrote the report entitled "Effectiveness of Wildlife Warning
Reflectors in Reducing Deer-Vehicle Accidents in Washington
State." They described an experiment from 1981 to 1984 in which
reflectors in four test sections were alternately covered and
uncovered. Resulting figures showed fifty-two deer killed in the
test sections at night while reflectors were covered and six
while they were uncovered. This significant difference suggested
"the reflectors were effective on this highway during this time
period."
Mary Ossinger's 1992 report on the ineffectiveness of
reflectors in Western Washington mentioned these Eastern
Washington tests and the conflicting results. She suggested the
difference might be due to the terrain and the species of deer
involved. The Eastern Washington test was in an area of open
ponderosa pine inhabited by whitetail deer, while the Western
Washington experiment took place in a densely forested area
populated by blacktail deer.
