The woman told the Colorado State Patrol that she saw the vampire in front of her car so she put her SUV into reverse and went into the canal in Mesa County.
She was not injured and her name was not released.
State Patrol says it does not believe drugs or alcohol was involved in the crash and the woman was not charged.
However, investigators say there is evidence the woman was not taking her prescribed medication.
This incident comes amid the hype surrounding the latest "Twilight" film, which was released on Tuesday.
(KUSA-TV © 2010 Multimedia Holdings Corporation)