Implementation and Evaluation of a Buried Cable Animal Detection System and Deer Warning Sign

Animal-vehicle collisions (AVC), and deer-vehicle collisions (DVC) in particular, are a major safety problem on Virginia roads. Mitigation measures such as improved fencing and location-specific driver alerts are being implemented and evaluated in Virginia and elsewhere. One of the most promising mitigation methods uses a buried cable animal detection system (BCADS) to provide roadside or in-vehicle warnings to approaching drivers based on the active presence of an animal on or near the roadway. BCADS may also be deployed in combination with exposure controls such as fencing to provide monitored, at- grade, animal crossing zones where conventional passages (e.g. culverts and bridges) are unavailable. In this study, the Virginia Department of Transportation (VDOT) in collaboration with the Virginia Tech Transportation Institute (VTTI) implemented and monitored the performance of a BCADS on a public road to provide a real-world assessment of system capabilities and possible operation issues. The BCADS has proved effective and reliable in a previous evaluation performed under more controlled and secure conditions at the Virginia Smart Road facility in Blacksburg, VA. A BCADS was installed on State Route 8 in the town of Christiansburg, VA on a road segment known to have a relatively high rate of DVCs. The system identified crossings of large- and medium-sized animals and provided data on their location along the length of the sensing cable. The BCADS and associated surveillance and communications equipment were powered by a solar photovoltaic system. A cellular modem provided for remote system monitoring and data collection. A flashing light “Deer Crossing” warning sign was installed at the site and was wirelessly linked with the BCADS to alert approaching drivers when an animal crossing was detected. Continuous BCADS and all-weather video surveillance data were collected during an 11-month period (November 2017–September 2018) to monitor animal movement, vehicle traffic, and system performance. Data on driver response to the activated warning sign during the dawn and dusk hours were collected in two separate daily sessions within a 3-month period. Study findings indicate that the BCADS is capable of detecting larger animals such as deer, and sometimes smaller animals such as coyotes, with approximately 99% reliability. The system also performed well when covered by approximately 60 cm (2 ft.) of snow. Moreover, the system was tested under various vehicle traffic conditions, and rare instances of relatively minor interferences were observed. Vehicle speed and brake light application data collected during warning sign activation showed that approximately 80% of drivers either braked or slowed in response, indicating that the sign was effective.