WASHINGTON (Reuters) -- People who talk on cell phones while driving, even using "hands-free" devices, are as impaired as drunk drivers, researchers said.

"If legislators really want to address driver distraction, then they should consider outlawing cell phone use while driving," said Frank Drews, an assistant professor of psychology at the University of Utah who worked on the study.

Drews added alcohol was involved in 40 percent of the 42,000 annual U.S. traffic fatalities. Just like many people who have been drinking, the cell phone users did not believe themselves to be affected, the researchers found.