Federal accident investigators recommended Tuesday that states cut their threshold for drunken driving by nearly half, matching a standard that has substantially reduced highway deaths in other countries.

The National Transportation Safety Board said states should shrink the standard from the current .08 blood alcohol content to .05 as part of a series of recommendations aimed at reducing alcohol-related highway deaths.

An NTSB study suggested dropping the blood alcohol content level threshold could cut down the nationwide number of drunken driving deaths by as much as 10,000.

"Studies show that about four-million people a year admit to driving while under the influence," said Louisiana Highway Safety Commissioner Col. John LeBlanc, "which becomes a great public safety issue because even if you're not drinking and driving, you and your family could be at risk for someone who's intoxicated."

It took 21 years for all 50 states to comply with the current alcohol content level the last time NTSB made a recommendation, LeBlanc said. Louisiana made that switch in September 2003.

More than 100 countries have adopted the .05 alcohol content standard or lower, according to a report by the board's staff. In Europe, the share of traffic deaths attributable to drunken driving was reduced by more than half within 10 years after the standard was dropped.

The Associated Press contributed to this report.