In partnership with advisory board member, Amy O’Leary, Ph.D., Associate Director for Environment, Planning and Economics Research at the Virginia Transportation Research Center (VTRC), VA’s LTAP is pleased to present a series of on-going research spotlights. Every few months, we’ll bring you updates about research being put into action to increase efficiencies and provide sustainable transportation solutions.


This month’s Research in Action features an evaluation of roadside behavior of animals, particularly deer, to determine strategies to reduce animal-vehicle collisions along our highways. Virginia is consistently among the top 10 states with the highest number of deer-related collisions (DVCs), with more than 56,000 DVCs per year since 2007. These collisions result in significant loss of life for animals, millions of dollars in damage to vehicles and increased risks for driver safety.

Mitigation strategies to reduce DVCs typically aim to either influence driver behavior, such as deer signs and animal detection systems, or animal behavior, such as roadside reflectors and wildlife crossings. These crossings, such as bridge and culvert underpasses, allow animals to cross over or under a roadway and are especially effective when fencing is used to help funnel animals toward the crossings.  Many new highway construction projects incorporate animal crossings into their overall design, often placing safe crossings every half-mile. However, less attention has been given to leveraging existing infrastructure, often spaced miles apart, to provide safe passage.

Bridget Donaldson, a research scientist with VTRC, along with colleagues Young-Jun Kweon, PhD, PE, and Lewis Lloyd, targeted a section of I-64 near Afton Mountain, focusing on animal activity near two unfenced underpasses and a stream corridor/highway intersection with no viable underpass. VDOT and the FHWA sponsored the project based on the high incidence of vehicle collisions with deer and bear along this stretch of highway. The agencies were interested in the types of mitigation strategies that might work based on animal activity patterns and how these strategies might be retrofitted with existing infrastructure.

Strategically-placed cameras captured significant roadside activity, such as walking and grazing, particularly in October and November, demonstrating a statistically significant seasonal relationship between roadside deer activity and DVCs. Over the two-year study period, 474 DVCs and 14 bear-vehicle collisions were documented representing an average of nearly 7 DVCs per mile per year.

The study found that topography, forest edges and stream corridors strongly influence deer movement, having the effect of funneling animals toward specific sections of the highway. These areas are prime targets for driver warning systems and signage. Seasonal patterns of activity suggest that dynamic warning signs would be effective, reducing the potential for drivers to become habituated to year-round warnings.

The researchers also recommended the installation of fencing adjacent to underpasses to guide animals toward safe crossings. They estimated that fencing both sides of just one underpass could result in savings of costs associated with DVCs of over $500,000 over its service life.

“There is great potential for low-cost mitigation strategies, such as fencing and driver alert signage, to be implemented on a large scale,” explained Donaldson. “Once we’ve identified habitats that exist around transportation infrastructure and can anticipate the animal activities that occur there, we can begin to implement cost effective strategies to substantially reduce unwanted interactions between drivers and wildlife.”

Fencing is currently being placed at one of the sites, with additional fencing to be placed at the second site later this spring. Cameras will again be installed to monitor the effectiveness of the fencing on the movement of animals. The researchers have begun testing the effectiveness of changeable message signs to reduce driver speed and ultimately reduce the number of animal-vehicle crashes. Preliminary results look promising.

For more information, contact Bridget Donaldson at

About VTRC

The Virginia Transportation Research Council (VTRC) is one of the country’s leading transportation research centers. Specializing in applied research to support VDOT, its scientists and engineers also provide technical consulting and training to promote innovations in structures, pavements, materials, safety, operations, traffic engineering, planning, environmental, and economic issues.

The goal of VTRC is to conduct research that enables VDOT to deliver transportation initiatives that save lives, save time and save money, while protecting Virginia’s environment.

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