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Road Management Journal
Copyright © 1997 by TranSafety, Inc.
August 11, 1997
TranSafety, Inc.
(360) 683-6276
Fax: (360) 335-6402
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Swareflex Wildlife Warning Reflectors: One Preventive Measure for Wildlife-Vehicle Collisions
Discussion of Sign Management Technologies
Questions with Answers from a Gravel Road Expert
Announcement and Call for Papers: Seventh International Conference on Low-Volume Roads
Tires: A New Source for Culvert Pipe

Highway Safety Publications Catalog. Articles on Road Engineering, Road Maintenance & Management, and Injury Litigation. Information and consulting for the Automobile and Road User, as well as for law professionals in accident investigations.
TranSafety's free consumer journal for automobile and road users, three subscription journals on road maintenance, engineering, and injury litigation, and highway safety publications catalog. See our free consumer journal for automobile and road users, three subscription journals on road maintenance, engineering, and injury litigation, and a highway safety publications catalog.


Swareflex Wildlife Warning Reflectors: One Preventive Measure for Wildlife-Vehicle Collisions

Some research efforts have reported success using Swareflex Wildlife Warning Reflectors to decrease vehicle-wildlife collisions. This article provides information on these reflector systems.

How Wildlife Reflectors Work

Tested with positive results in Austria in the early 1970s, Swareflex Reflectors were introduced in the United States shortly after that. The reflectors are about six inches by two inches and mount on posts. Secured at the average height of vehicle headlights, reflective devices are installed at regular intervals along both sides of the roadway. The devices reflect headlights to create a low-intensity red beam that bounces across the roadway and into woods and ditches at the side of the road. Motorists do not see the reflected light. Animals, however, come upon the unnatural and seemingly moving light patterns and do not cross the roadway while the lighted "fence" is present. After the vehicle passes, the light pattern collapses and animals go freely on their way.


Democrat & Chronicle, Rochester, NY

Although reflector systems do not function during daylight hours, a significant majority of wildlife-vehicle collisions happen between dusk and dawn. Therefore, such systems have been shown to reduce overall animal-vehicle collision rates by 60 to 90 percent. Evidence suggests reflectors systems are effective for deer, elk, moose, fox, coyote, raccoon, opossum, and cougar.

Strieter Corporation is the exclusive distributor and importer of Swareflex Reflectors for the United States and Canada. The company has recently introduced a model of the Swareflex Reflector called STRIETER-LITE. This model allows simplified spacing of reflectors, even in areas where terrain is both sloping and level. It also takes fewer STRIETER-LITE reflectors to successfully deter animals from crossing the road when a vehicle is passing, thus cutting the costs of installation and maintenance.

Installation and Maintenance Costs

In their April 3, 1993 Status Report, the Insurance Institute for Highway Safety called roadside reflectors "the most promising system for preventing deer crashes." They added, however, that "substantial investment is required for installation and maintenance."

Installation and maintenance costs of reflector systems vary. Reflectors themselves are $17.95 each (U.S. price), with a discount of 5 percent on orders for 2,000 or more reflectors. Additional expenses to put in the system include mounting posts, hardware, and labor for roadway clearing and reflector installation. The Strieter Corporation estimates a total average installation cost of $7,000 to $10,000 per mile for a two-lane, two-way road.


Reflector Installation

* Illustration source listed at the end of the article

Proper maintenance is essential for effective functioning of the reflector system. When reflectors are broken, knocked down, or misaligned, the gaps in light pattern that result are like an opening in a fence. Heavy dirt, frost, or snow will also keep devices from reflecting headlights effectively. Evidence shows animals will cross the road where these gaps occur; therefore, crews need to check for and replace broken or missing reflectors, realign skewed devices, and clean reflectors at least twice a year. Feedback to the Strieter Corporation regarding costs suggests an estimated expenditure of $500 per mile per year to replace and maintain a wildlife reflector system.

Steve Chicka, Highway Engineer for Fond du Lac County in Wisconsin, shared with Strieter Corporation his experience with maintaining reflectors. He wrote, "In 20 minutes, 1 man can clean all the reflectors in a mile stretch of highway simply by using a pail of water and a sponge."

Michigan's Local Technical Assistance Program placed at $2,000 the average cost of vehicle damage from a deer-vehicle collision. Therefore, a wildlife reflector system would be cost effective in the first year ( based only on the savings in vehicle damage) if installation resulted in four to five fewer deer-vehicle collisions per mile per year.

In addition to vehicle damage, deer-vehicle collisions annually account for more than 100 motorist deaths and over 7,000 injuries. These deaths and injuries are a personal tragedy and a major economic loss to society. Considering the total cost of wildlife-vehicle collisions, successful preventive measures could be highly cost effective.

Funding Sources

In an October 1995 letter to Strieter Corporation, Rudolph M. Umbs of the Federal Highway Administration's Office of Highway Safety wrote, "Your product does appear to be effective in reducing the number of animal roadway crossing accidents." Such devices, he explained, are "eligible for Federal-aid funding under PL 102-240 (ISTEA) SEC. 1007." Umbs suggested those interested in installing wildlife warning reflectors should contact their state highway agencies for information on funding assistance.

A Strieter Corporation information sheet on federal government funding for the new STRIETER-LITE reflectors indicated, "Minnesota has been funding all Strieter- Lite/Swareflex projects with Federal Hazard Elimination Funds for over five years." The corporation also suggested, "Any state, county, or city which wants to apply for Federal Surface Transportation Funds/Hazard Elimination Funds (80% Federal; 20% State/Local) must go through the State Highway Department and the FHWA Division office to gain approval."

More Information

While some experiments with Swareflex Reflectors have reported significant success, others have not. Many factors may affect how well the devices will work to prevent wildlife-vehicle collisions on a specific stretch of highway. Among others, these factors include: the species of deer or other wildlife that inhabits the area, the type of vegetation at the sides of the highway, the migration pattern of the animals, annual fluctuations in herd size, habitat changes due to forest fires, the slope of roadside embankments, and the volume and speed of passing traffic.

The best way to find out if warning reflectors will reduce the number of wildlife-vehicle collisions in an area with a high collision rate is to set up a test section. Test results will not be accurate, however, unless reflectors are correctly installed and properly maintained. Crews must replace broken, misaligned, or downed reflectors as soon as possible and clean the devices at least twice a year. Accurate records must be kept to determine the wildlife-vehicle collision rate when reflectors are in use and when they are not. In addition, testing methods must take into account factors, such as those mentioned above, that affect the way reflectors work. Controlled, long-term experimentation that generates accurate records for substantially equivalent intervals when reflectors are covered and uncovered is the best indicator of how the devices will perform on a specific section of roadway.

To receive detailed information about successful experiments with Swareflex Reflectors and about the costs, installation, and maintenance of the STRIETER-LITE wildlife warning highway reflector system, call, fax, or write:

Strieter Corporation
2100 Eighteenth Avenue
Rock Island, Illinois 61201-3611
(309) 794-9800
(309) 788-5646 (fax)

* Illustration taken from Effectiveness of Wildlife Warning Reflectors in Reducing Deer-Vehicle Accidents in Washington State by James A. Schafer, Stephen Penland, and William P. Carr, August 1984.

Copyright © 1997 by TranSafety, Inc.


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