Longwell said the average blood alcohol level in alcohol-related traffic fatalities is .16.
Almost 10,000 people are killed - and 173,000 injured - each year in drunk driving crashes, the NTSB said. Though improvements in auto and highway safety, as well as effective crackdowns on drunk driving, have seen a decline in roadway fatalities in recent years, about 30 percent of all deaths continue to be alcohol-related.
"Most Americans think that we've solved the problem of impaired driving, but in fact, it's still a national epidemic," Hersman said. "On average, every hour one person is killed and 20 more are injured."
The Insurance Institute for Highway Safety, a insurance industry research group, confirmed Tuesday that the risk of impairment to driving can occur well before a drinker reaches the .08 level.
"We would expect some effect if states lowered the threshold to .05, but since no state has passed such a law, it hasn't been evaluated here," said Anne McCartt, the institute's senior vice president for research. "One difficulty in the U.S. is enforcement. Impairment begins well before the classic signs of impairment may become evident to a police officer, like a driver weaving. Since testing for impairment follows arrest, not the other way around, enforcing such a law would be a hurdle."
The NTSB said almost 440,000 people have died in accidents tied to drinking in the past three decades.
In findings released with its recommendations Tuesday, the NTSB said that alcohol levels as low as .01 have been found to impair driving skills, and that a level of .05 has been "associated with significantly increased risk of fatal crashes."
The board said a .05 limit would significantly reduce crashes and deaths.
In a recommendation made last year, the NTSB asked states to require ignition interlocks for all drivers convicted of drunken driving.
Longwell said the recommendation of a .05 limit for all drivers had implications for another emerging technology.
A prototype vehicle expected to begin testing later this year will be equipped with passive devices that eventually could be a standard feature in all vehicles, to test how much a would-be driver has had to drink.
"Where are they going to set this technology?" Longwell said. "They've been saying it's .08. Well, the question is, if you lower the legal limit, where do you set the technology in all cars?"
Daily Mail writer Ashley B. Craig contributed to this report.
Other Top Headlines