SILVERTHORNE, Colo. -- A 3-mile stretch of Interstate 70 has been designated a moose-crossing zone in an attempt to stem brushes between the animals and high-speed traffic.

The crossing zone covers a stretch between Silverthorne and Frisco.

During the past few years, moose following the Blue River have wandered across four lanes of high-speed traffic or stood on the highway.

The animals are about 6 feet tall at the shoulders, and hitting a 1,200-pound moose at 75 mph can be like colliding with a semitrailer.

"The problem is they are so tall that when an average car hits one, its belly misses the bumper and hood and goes right into the windshield," said Kirk Snyder, a district wildlife manager in Walden.

Three drivers near Silverthorne, Dillon and Frisco recently ran into moose, killing the animals and heavily damaging their vehicles, said Tom Kroening, district wildlife manager in Silverthorne. The drivers were going slow enough that no people were injured, he said.

On Sunday, a moose and her offspring (pictured, left) stood in the middle of the interstate. Sometimes up to five have been spotted on the road at once.

The moose were tranquilized moved by trailer to their new home in the Williams Fork drainage.

“They both came out of immobilization really well and wandered off into the night. Both looked to be in great shape,” said Andy Holland, a wildlife biologist in Hot Sulphur Springs who assisted in the relocation.

"We want to talk to the Colorado Department of Transportation about putting electronic signage along there to warn motorists before something really bad happens," Kroening said.

In the past nine months, two moose were hit on U.S. 34 between Granby and Grand Lake and another on U.S. 40 near Winter Park, said Andy Holland, a state wildlife biologist.

North of Walden, three moose were hit on Colorado 125, Snyder said.

As recently as 25 years ago, moose were extremely rare in Colorado, with only a few stray moose wandering into northern Colorado from Wyoming herds. In 1978, the DOW arranged for the first transplant of 12 moose to Colorado’s North Park region near Walden. In 1979, another dozen were released in the same region. The North Park population grew and expanded into the Laramie River Valley, and was boosted by an addition of 12 moose in the Valley in 1987.

The success of the North Park population allowed DOW officials to move part of that population along with added individuals from Wyoming and Utah and release about 100 moose in southern Colorado near Creede.

“The moose populations are doing well,” Holland said. “The populations are increasing and their range is expanding.”

Biologists said that current moose populations are estimated at 500 animals in North Park and 250 in Middle Park with ranges expanding into Summit County, Gunnison, western Larimer and Boulder Counties and new areas in Routt County. Colorado’s population is now estimated at between 1,300 and 1,400 individuals statewide.