Collision Course

Things are getting safer for those who wander Arizona's highways, especially if those wanderers happen to be elk.

One 17-mile stretch of Arizona highway logs significant elk and car collisions each year, said Norris Dodd, a wildlife research biologist at the Arizona Game and Fish Department in Pinetop, Ariz. "Those strikes killed at least 100 elk in 2004."

Dodd said the state wants to find a cost-effective way to virtually eliminate the elk-strike problem. After all, he noted, a grown elk weighs between 600 pounds to 1,200 pounds.

"Whenever people hit an elk," he said, "there is going to be a lot of property damage and potential human injury."


Elk Walks
Dodd's office is working to curb the carnage. Scientists are building an electric fence to dissuade the animals from randomly crossing the highway by channeling the elk to particular points. State officials put openings in the fence at traditional elk crossing spots, with the idea that the animals will move along the fence until they come to these "crosswalks."

In addition to herding the elk toward safe crossings, infrared sensors also warn motorists of possible animal hazards, encouraging them to slow as animals near the crosswalks.

"If the motorists respond," Dodd said, "it helps create a situation where the animals can be funneled [to the safe zones], where they can be made to cross."

Crossing locations have been chosen by the elk themselves. Fitted with GPS collars, they simply followed their accustomed routes, leading planners to the most likely points for successful crossings.


Cost Factors
The private sector stands to benefit by the success of Arizona's project. The National Highway Traffic Safety Administration reports an estimated 1.5 million deer-vehicle collisions in the United States each year, causing approximately 150 deaths and $1.1 billion in property damage annually.

In October 2006, insurance giant State Farm reported that policy-holders were involved in 192,877 deer-related collisions in 2006, with an average property-damage cost of $2,800 per incident.

Because of the financial implications of vehicle/wildlife collisions, the pilot project has drawn a $1 million state grant. The test is deployed along a short stretch of Arizona State Route 260, near the town of Payson.

The departments of Transportation and Game and Fish share the cost of the project. Besides the infrared crosswalks, the main expense lies in the construction of 11 sets of underpasses at $2 million to $3.5 million each. Bridge crossings will further increase the cost, Dodd said, adding that if successful, the infrared system could save significant dollars in the future by eliminating the need for further underpasses and bridges.

At the same time, he said, competing priorities will always be an issue. "Highway dollars are quite limited, and we have a lot of other problem areas."


Early Warning
The strategy is to warn motorists of animal hazards. As animals approach the designated road crossings, infrared cameras from Canadian electronics company Electrobraid Fence will pick up thermal signatures from the animals. Military-grade target acquisition software helps distinguish critters such as squirrels and rabbits from larger-sized animals.

When the software identifies big game, sensors trigger the deployment of a pair of solar-powered road signs. A first sign warns drivers that they are "entering elk testing area"; a second sign says, "elk ahead, slow down."

If drivers can be trained to respond to the signs, Dodd said, the warning system could eliminate the need to push elk toward the underpasses.

The project has been unfolding for about five years and will be fully deployed by the end of 2006, Dodd said, just in time to help protect the animals during the colder months that typically force them down from the mountains, into lower elevations and onto the highways.

Despite the ongoing deployment of an 8-foot-tall electronic fence along much of the 17-mile section of highway and enough cameras to cover each side the highway at the crossings, it is still difficult to gauge the relative the project's success.

Though Dodd said fenced areas have seen an 83 percent reduction in elk-vehicle crashes during the last year, speeds in the 55 mph test area still average 80 mph. Over the long term, Dodd said the elk-accident rate has nearly doubled in seven years, with 36 percent of those incidents happening at designated crossings.

Dodd said the fault lies in the state's exploding population, not the warning system. From 1990 to 2000 the state population density swelled from 32.3 people per square mile to 45.2, according to state statistics. Headcount is expected to grow from 3.6 million in 1990 to 6.6 million by 2010.

To counter the population boom, planners are laying the groundwork for a public education campaign, while also working to expand the reach of the electric fence, to better channel elk toward the crossings.