Animal-vehicle collisions affect human safety, property and wildlife. The number of these types of collisions has increased substantially over the last decades. This report describes the results of a project that explored the prospects for a relatively new mitigation measure to reduce animal-vehicle collisions: animal detection systems. Animal detection systems use high tech equipment to detect large animals when they approach the road. Once a large animal is detected, warning signs are activated urging drivers to reduce the speed of their vehicles, be more alert, or both. Lower vehicle speed and increased alertness may then lead to fewer and less severe collisions with such animals as deer (Odocoileus sp.), elk (Cervus elaphus) or moose (Alces alces). This report documents Phase I of the project (October 1999 - December 2005). The report identifies existing animal detection system technologies and their vendors; describes the selection of two experimental detection systems and their installation at two field sites; documents the experiences with planning and design, installation, operation and maintenance; documents test results on the reliability of the two systems; documents system acceptance; and provides advice for the future development and application of animal detection systems.