Video shows the elk running toward people Thursday near the visitor center in Estes Park near Rocky Mountain National Park.
The woman escaped after public works employee Brian Berg drove a pickup on the sidewalk and got between her and the elk.
The elk then rammed the front of the truck.
A spokesman for Colorado Parks and Wildlife, Jason Clay, told KDVR-TV that bull elk aggressively fight over their breeding rights.
He said people need to give elk space even in developed areas and let them move away on their own.