Designated driver may not always be sober

ATLANTA, Dec. 30 (UPI) -- The effectiveness of naming a designated driver may be determined by how the designated driver is defined, U.S. health officials said.

Officials at the Centers for Disease Control and Prevention said the varying definition of a designated driver is among the challenges facing researchers who study the effectiveness of designated driver programs.

The most common definition requires that the designated driver abstain from alcohol, be assigned before anyone in the group starts drinking and drive group members to their homes at the end of the event or gathering.

However, another definition is based on the concept of risk- or harm-reduction -- the designated driver needs only to maintain a blood alcohol content limit that is under the legal limit.

In practice, many people may apply the designated driver concept in ways that are unsafe such as choosing the person in the group who is least drunk to be the designated driver, the researchers said.

Federal health officials advise:

-- Always designate a non-drinking driver before any holiday party or celebration begins.

-- Don't let friends drive if they are impaired.

-- If you're hosting a party, remind guests to plan ahead and designate their sober driver; offer alcohol-free beverages; and make sure all of your guests leave with a sober driver.