Rocky Flats National Wildlife Refuge (“the Refuge”) in Colorado near Denver, Colorado, has a history (1952-1989) of producing components for nuclear weapons. The current goal for the area is “to restore and preserve the native prairie ecosystems, provide habitat for migratory and resident wildlife, conserve and protect habitat for Preble’s meadow jumping mouse, and provide research and education opportunities”. The grasslands of the Refuge are surrounded by busy roads to the west (Hwy 93, 18,000 AADT), north (Hwy 128, 4,200 AADT) and east (Indiana St. 7,000 AADT), and there are houses and associated roads on its southern boundary. Other open space with non-motorized trails and protected areas with predominantly grassland are to the west, north and east. Large ungulates, including mule deer, elk, and moose cross the roads. This results in large ungulate-vehicle collisions and the roads also represent a barrier to the movements of animals. Creek crossings under the roads are a concern as they are likely a barrier for species dependent on riparian habitat, including the Preble’s meadow jumping mouse. The objectives of the current project were to 1. Formulate measures that reduce collisions with large wild mammals, and 2. Formulate measures that improve connectivity across roads for large wild mammal species and one small mammal species in specific, the Preble’s meadow jumping mouse. We suggest large open span bridges at creek crossings (for deer, moose, black bear, mountain lion, and Preble’s meadow jumping mouse) and designated wildlife overpasses for elk and also for mule deer. The crossing structures may be combined with human co-use to connect the trails on the refuge with the trail system in the surrounding areas.