Successful Installation in Wisconsin
Wayne R. Wilson
Retired Wisconsin State Trooper

This 5 minute YouTube video, The Problem of Deer-Vehicle Accidents and the Solutiondescribes how reflectors mounted on posts near the side of a highway dramatically reduce the number of deer-vehicle collisions. When a car passes, light from the headlights is directed to the side of the road and is seen by deer that wish to cross the highway as a row of sequential flashing lights. This startles them and causes them to wait until the vehicle passes before crossing the highway.

The setting is Menomonie, Wisconsin in October 1995.

Deer Warning Roadside Reflectors
Marvin Denberg
Oct. 15, 2001

Increased traffic and deer population along with new suburban developments have increased the possibilities of car-deer collisions. These accidents are frequently very traumatic and may result in personal injury, vehicular damage and serious or fatal injury to the deer. After a careful review of information and road test data, it is my conclusion that deer warning roadside reflectors offer the best solution to the problem.

The reflectors are designed to work in the dusk-to-dawn hours when over 75% of car-deer accidents occur. The reflectors pick up car headlights and direct a reflected beam at the deer, deterring them from crossing roads in front of oncoming traffic. It is recommended that the reflectors be installed along roadways where previous car-deer accidents and/or heavy traffic and large numbers of deer crossings indicate a significant potential for these type of accidents. The basis for this recommendation was a detailed review of extensive road test data showing an average reduction of 88% in car-deer accidents after installation of the reflectors.

The Strieter-Lite deer warning roadside reflector system comprises a series of red reflectors placed along both shoulders of a road in a staggered pattern. If deer are about to cross a road into oncoming traffic, the deer see an unnatural moving red reflection from the approaching vehicles' headlights bouncing off the reflectors and are deterred from crossing until the vehicle has passed. Since the deer's night vision is much more sensitive than that of humans, the weak reflections are not bothersome to persons in the area but are very prominent to the deer. The Strieter-Lite reflectors are the only ones incorporating the patent design providing full no-gap coverage and have demonstrated superior proven performance in extensive, long term road tests.

Basis for the conclusion of the effectiveness of the reflector system was a detailed analysis of all available field test data obtained from the 13 states and British Columbia where accident data rates prior to and after reflector installations were recorded. The data represents a total of 53 individual test sites covering a total of 52 miles. The average reduction of 88% in car-deer accidents corresponds to preventing almost 9 out of 10 accidents from occurring. Analysis of the accident data for all test sites including the duration of the pre and post reflector test periods, length of the road test site, and the recorded number of car-deer accidents prior to and after reflector installations provides a figure of merit that indicates the estimated number of accidents that will be prevented for a selected site. The data reflects an average accident rate reduction of approximately 10 accidents per mile per year. This is a very significant accident prevention technique that greatly enhances car travel safety where deer crossings are of concern.

The cost for the Strieter-Lite reflector system, including material and installation labor, is about $8,000 per mile. Since the reflectors are installed on selected roadways where accidents have previously occurred or deer crossings are prevalent, it can be expected the system will pay quick dividends. The average cost for a minor accident involving vehicular damage and no personal injury is about $2,500. Therefore, even if only 4 minor accidents can be prevented in one mile of highway in one year-the system will pay for itself in a little more than a year. Since the road test data indicates that an average of approximately 10 accidents per mile per year can be prevented, the pay back time can be expected to be much shorter, averaging less than 4 months. It is of interest to note that compared to sound barrier installations along roadways, the cost for reflectors is minimal. 15 miles of reflectors can be installed for the cost of about 100 feet of barriers.

The deer warning roadside reflector system is a proven, cost effective concept that is here today and works very well. Roadside reflectors are a safety device that significantly reduces car-deer accidents preventing personal injury, the great trauma involved in this type of accident, and vehicular damage, as well as reducing the number of deer killed and injured. There is no other known approach that has proven to be effective in significantly reducing car-deer accidents.

Eyewitnesses of Deer Behavior near Reflectors 
John Strieter
August 17, 2011

At least five people have witnessed and reported on various types of deer behavior on the roadside near the deer reflectors. One observation made in Canada was that as deer were running toward the road from an angle, they would veer off and leave the area. Another person from Algoma, Wisconsin reported seeing running deer approach the road perpendicularly, come to a stop, turn around, and run away faster than when approaching - as if frightened.

Light coming from Strieter-Lite reflectors do not frighten deer standing or grazing along the roadsides, but do deter those running towards the road to cross. Running deer are more likely to react to moving objects such as the light reflected from these reflectors than when the deer are stationary or grazing.

Just because the deer do not move away from the lighted reflectors while grazing (as reported by some observers) does not mean that the reflectors are ineffective. Most likely the deer are content where they are, have no need to cross the road, and are therefore not looking toward the reflectors.