Animal passage systems can be designed to facilitate movement of certain wildlife species across highways. Where the conservation of a particular species or group of species is concerned, specifically designed mitigation has proven successful for a number of species. However, the effectiveness of highway mitigation systems has not been evaluated with respect to the vast majority of wildlife. It is probable that some species do not require specific design features while others will require careful attention to factors such as placement, size, substrate, noise, temperature, light and moisture. In areas where road and highway density is high, conservation of particular species may be of lesser concern than the maintenance of overall habitat connectivity. While it is impractical to design mitigation projects that account for the specific requirements of all species affected by a highway, it may be possible to develop a generalized strategy for making highways more permeable to wildlife passage for a larger number of species. This strategy will require use of a variety of techniques given that the specific requirements for particular species may be contradictory. Some of the most effective techniques for facilitating wildlife movement (i.e. overpasses) are also quite expensive. A practical strategy for mitigating highway impacts on wildlife movement may dictate that expensive elements be reserved for areas that are identified as important travel corridors or connections between areas of significant habitat, while inexpensive elements (amphibian and reptile tunnels) can be used at appropriate areas throughout the highway alignment. In developed areas, corridors and habitat connections may be readily apparent. For highway projects affecting a significant amount of undeveloped land it may be necessary to conduct landscape analyses to identify “connective zones” for special mitigation attention.