The National Transportation Safety Board voted earlier this month to encourage states to lower their current legal blood alcohol content limits for drivers from .08 to .05 percent, saying the change would save lives.

Mothers Against Drunk Driving founder Candace Lightner, who led the successful national campaign in the 1980s to crack down on drunk driving after her daughter was killed in an alcohol-induced accident, doesn't support the proposal.

"I don't believe it is a practical long-term solution," Lightner told U.S. News. "You could go to 0.0 and that would save lives. You could go to a 40 mph speed limit and that would save lives, but you have to look at what's realistic."

The laws would likely save lives in the short-term due to media attention, she said, but ultimately "won't be enforced and will be a waste of time," distracting from what Lightner sees as the most significant highway safety issues: high-BAC drunk driving, drugged driving and distracted driving.

States set their own legal BAC limits, but since 2004 all 50 states have had a legal limit of .08, at the urging of MADD and the NTSB.

"Years ago, I wasn't really hot on .08," said Lightner, who left MADD in 1985. "I didn't think it would be enforceable and that it would work, and I've heard it isn't being enforced. But we're at .08 now, so I'm going to say leave it there."

MADD's current leadership signaled that it won't actively push to lower the legal blood alcohol limit, which the NTSB predicts could save 1,000 lives a year.

"Running around trying to arrest everyone at .05 is impractical," Lightner says. Police and prosecutors she spoke with said the lower limit would be "very hard to prosecute," in part because many of those drivers would pass a field sobriety test, leaving only subjective evidence of impairment.

Stephen Talpins, a Miami attorney who spent 12 years as a prosecutor in the Florida state attorney's office before leading the National Traffic Law Center and serving as MADD's public policy director, told U.S. News that jurors would likely be disinclined to convict people arrested with alcohol levels between .05 and .08.

"We don't criminalize less-safe conduct in every instance," said Talpins, now chairman and CEO of the National Partnership on Alcohol Misuse and Crime. "The vast majority of people below .08 will pass a field sobriety test."

"Under the current law, you're guilty if you provide a sample of over .08 or higher, but you're still guilty if you're impaired at a lower level," Talpins pointed out, meaning that the lower limit would only affect people below .08 who do not appear impaired. "Do we want to criminalize someone having a .05 BAC who does not appear impaired to anyone?" he asked.

Lightner recently formed a new organization, We Save Lives, to coordinate among groups that oppose drugged and distracted driving. The group is calling on President Barack Obama to form a national task force to tackle drugged driving, similar to the one appointed by President Ronald Reagan to address drunk driving.

Lightner remains proud of her work to raise the national drinking age to 21 as a way to reduce drunk driving. "I was the one who initiated raising the drinking age to 21 and I stand by it," she said. "That was my thing. I believe in it strongly and support it all the way."

After leaving MADD, Lightner became critical of the group she helped build into a national activist organization, referring to it as "neo-prohibitionist," But she now says that disagreement is over. "I believe they're off that kick," Lightner said. "It was a long, long time ago. Unfortunately the Internet has a habit of keeping old comments alive."

"I know they're following [We Save Lives] on Twitter, so good for them," she said of MADD.