Consider dynamic natural conditions and surrounding landscapes when selecting technologies for animal detection system deployments.
Montana and Pennsylvania’s experience with deploying animal detection systems.
Thompsontown,Pennsylvania,United States; Yellowstone National Park,Montana,United States
- Employ solar power as a cost effective means for powering animal detection systems. Most animal detection systems are located in rural and remote areas where 110 V or 220 V, if available, may be relatively expensive to bring to individual sensor stations.
- The cost for trenching and conduit alone, to two sides of the road, over a half mile, was estimated to be a minimum of $52,983 at the site near Thompsontown, PA. In contrast, the total cost for solar power was estimated at $7,500.
- Anticipate the occurrence of false positive and false negative detections and plan accordingly. False positives occur if the system is triggered by causes other than the presence of large animals and false negatives occur if a large animal is present, but the system fails to detect it. Frequent false positives may cause drivers to eventually ignore activated signs, while frequent false negatives present drivers with a hazardous situation. False positives and false negatives may have a wide variety of causes, though the systems at the Montana and Pennsylvania sites suffered especially from the causes shown below:
- False positives
- Faulty hardware
- Hardware that does not meet the requirements (e.g., temperature range)
- Incorrect signal strength
- Inability of the software to distinguish between true and false detections
- Software errors
- High, moving and wet vegetation
- Passing traffic
- Heavy snowfall with high moisture content
- Snow spray from snowplows and other vehicles
- Snow and ice accumulation in front of the sensors
- Snow accumulating on the ground and covering the sensors;
- Vehicles turning on and off the road
- Vehicles parked in the right-of-way; and
- Accumulating snow on the ground, blocking or bouncing signals.
- Incorrect location or height of sensors, leading to blind spots in curves or low areas in the right-of-way;
- Faulty hardware
- Incorrect software definitions (settings) for valid detections;
- Snow accumulation on ground leading to incorrect sensor height at high snow levels
- Sensors that are out of alignment (possibly due to expansion and shrinking of wooden poles with varying temperature and moisture contents
- Vandalism or perhaps the rubbing against equipment by large animals, (e.g., elk or bears).
- Provide for remote access to optimize the deployment of resources. While not essential to the functioning of an animal detection system remote access to gather and analyze data and other parameters (e.g., battery voltage, output of solar panels) will save time and money as it allows basic system functions to be checked without conducting site visits. Remote access can allow for the disconnection of certain sensors or stations if an isolated problem, that cannot be immediately resolved, is detected. The functioning sensors will then remain in operation and will warn drivers when large animals approach the road in the sections with the active sensors or stations. In addition, remote access may allow for the connection or disconnection of the flashing warning signs and changing the time that the lights flash after the last detection has occurred. Data logging can be accomplished by allowing the animal detection equipment to periodically and autonomously download to an online database. Under this procedure, the detection equipment could produce reports whenever the data link is available. These data services are less expensive than “connection on demand” services and are readily provided by low earth orbiting satellites (LEOS) and cell phone systems.
- The system at the Montana site stored detection data on a flash card including: radio link failures, radio link signal levels, beam break summaries, logging memory status, station identification number and sensor, whether the flashing lights were turned on or not, battery voltage, solar panel voltage and temperature in the box with equipment. The last three parameters allowed for identifying potential problems. In addition, the logging system maintains and reports statistics associated with the operation of individual elements of the system. All data can be downloaded on-site or from a remote location through a modem and land-based phone line. The time delay for signal turn off could also be set from a remote location.
- In Pinedale, Wyoming a camera and recording system are used to help validate and calibrate the animal detection system. The camera system allows for remote monitoring from the local WYDOT office.
- At the animal detection site in Nugget Canyon, WY three separate systems are used which are all linked to one of three traffic counters to allow for remote access to the data.
- Ensure adequate coverage can be achieved when planning for remote access. Remote access can be obtained through a modem and a telephone connection (land based, cellular or satellite) or radio signals if one is in the immediate area. However, agencies deploying communications technologies need to take into account certain limitations and plan accordingly. For example, if connecting via cellar telephone thorough testing for signal strength is required, as coverage can be poor or variable, especially in remote and rural areas. Establishing what technologies are available based on any limitations, will allow agencies to deploy a communications system that will provide full functionality from the onset of its installation.
- At the Montana site cell phone coverage was insufficient for reliable data transmission. The poor performance of the telephone line connection to the Roadway Animal Detection System (RADS) encouraged the exploration of alternate communication methods for remote access. As a result a satellite based system was found which was tailored to this application. At the time the report was written it was the intention that this system would be demonstrated at the site along US Hwy 191 in Yellowstone National Park.
- Prevent obstruction of detection sensors by mitigating the effects of snow accumulation. The accumulation of snowfall on the ground and on RADS sensors can lead to a number of challenges in detecting the presence of large animals. Another factor that can cause problems for sensors is snow spray from snowplows and other vehicles. When deploying animal detection systems in areas where snowfall is possible, agencies need to seek methods or tools to ensure sensor detection will go unhindered during snow events.
- At the Montana site, because accumulation of wet snow can reduce the signal level of beams, radomes (shields) were added to the transmitter and receiver stations to prevent the accumulation of snow and ice in the beam tube aperture.
Author: Huijser, Marcel P., et al .
Published By: Oregon DOT
Prepared by the Western Transportation Institute - Montana State University, and Sensor Technologies and Systems, Inc. for the Oregon DOT
Source Date: August 2006
Other Reference Number: Report No. SPR-3(076)URL: http://www.oregon.gov/ODOT/TD/TP_RES/docs/Reports/AnimalVehicle.pdf
Volpe National Transportation Systems Center
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