7 Large Animal Crash Mitigation
7.1.3 Elk Warning System – Finland18
Impetus for the Activity
Twenty percent of crashes in Uusimaa in the 1990s were caused by elk. In 1995, there were 435 elk-related crashes reported; however, only seven percent of these caused injury. Upon further crash analysis, it was recognized that many of these crashes were clustered in specific areas making “Hot Spots” easily identifiable.
 Table 6: Effect of Elk Warning System on Vehicle Speed. |
System Description
The system is located on Highway 7 in the Uusimaa region of Finland. The location is a typical highway with a high incidence of elk crashes. Prior to the installation, elk were funneled into this specific crossing by 1,650 meters of elk fence.
Animal detection is accomplished by microwave radar sensors placed two per pole. Poles are placed 50 meters apart and 5-20 meters from the roadway. The total detection zone is 220 meters. Due to false detections, 16 passive infrared detectors and one rain detector were added. Lighted fiber optic signs are placed 200 meters upstream of the detection zone.
Although there were several months of working out bugs in the system, it was fully operational in mid-December 1996. The system cost approximately $90,000 and was supplied by Sabik, Oy (Finland).
System Effectiveness Evaluation
Speed was measured using loop detectors. As can be seen in Table 6, the sign was most effective at reducing vehicle speeds during rain. Before the modifications, only 1 in 107 alarms was positively identified as an elk.
Obstacles Encountered and Lessons Learned
There was concern that the Finnish National Road Administration did not own the right-of-way for the entire detection zone, and that development might affect the accuracy of the sensors. Another concern was that the numerous false alarms might deteriorate the driver confidence in the system. The causes of the false alarms and how they were dealt with include:
- Other movement (blowing grass, etc.): only movement of at least 0.8 meters per second toward the detector was counted as valid.
- Small animals (birds, squirrels, etc.): 0.5 seconds of continuous signal is needed for valid detection. Additionally, the vertical mounting of the detectors was adjusted to 3 m above ground
- Rain and wind: metal eaves were installed over detectors and a rain sensor was added.