Along Virginia's Interstate I-64 west of Charlottesville, the Virginia Transportation Research Council (the research division of VDOT) constructed wildlife fencing to direct animals to two existing underpasses that were not originally designed for wildlife. A camera monitoring study was conducted to determine the effectiveness of the fencing.
After fencing installation, deer crossings increased 410% at the box culvert and 71% at the bridge underpass resulting in an average reduction in vehicle crashes of 92%, with no increase in crashes at the fence ends. Use of the structures by other wildlife species increased up to 165%.
The addition of fencing to the existing underpasses was estimated to result in an average savings of more than $2.3 million per site over the lifetime of the fence.
You can find the journal article and a storymap of the project below.