South Carolina has the nation’s highest rate of traffic fatalities involving drunken drivers, but would a tougher DUI threshold make a difference?

The National Transportation Safety Board thinks it would, in South Carolina and across the nation.

The board this month approved recommendations aimed at reducing alcohol-related traffic deaths, including a controversial proposal to lower the blood-alcohol concentration level at which a person is presumed to be impaired from the current 0.08 to 0.05 or less.

At that threshold, some people, and particularly petite women, could have enough alcohol in their blood to support a DUI charge after a single strong drink.

South Carolina Sen. Gerald Malloy, D-Hartsville, already has introduced legislation to make 0.05 the new DUI standard. Several attempts to reach Malloy for comment were unsuccessful.

“We would definitely in South Carolina support that,” said Laura Hudson, vice president for public policy at the S.C. chapter of Mothers Against Drunk Driving. “Commercial drivers already have a limit of 0.04, and if experienced professional drivers have that limit, why would 0.05 be too low for other drivers?”

Hudson said MADD-S.C. is focused on getting a law passed to require ignition-locking devices on the vehicles of people convicted of DUI, so that they would have to provide a breath sample before driving. She doesn’t think passage of a lower DUI standard is likely this year.

The NTSB’s recommendation and Malloy’s legislation would be a substantial change in South Carolina. The law currently says a breath-test reading of 0.05 indicates a driver is not impaired.

“The science has not changed,” said Charleston lawyer Tim Kulp, a former prosecutor who now specializes in DUI defense.

“Our current law says that 0.05 or less establishes a conclusive presumption that you’re not under the influence.”

Kulp doesn’t think lowering the limit would reduce drunken driving, but worries that such a low limit could result in people who aren’t impaired being charged with DUI.

While South Carolina currently considers a driver unimpaired at 0.05, the NTSB says someone who has consumed enough alcohol to register a 0.05 has a 38 percent greater chance of being in a wreck. The board says action is needed to reduce alcohol-related fatalities that persistently account for nearly a third of U.S. highway deaths.

“This really isn’t about trying to eliminate people having a glass of wine or a beer with dinner,” NTSB Chairwoman Deborah Hersman told The Post and Courier. “It’s about eliminating more than 10,000 fatalities a year.”

Most of those fatalities cited by Hersman involved drivers who were driving impaired under current regulations. There were 1,633 highway fatalities in 2011 in which a driver had some alcohol in their system, but at a level below .08.

A one-beer DUI?

Remember the charts from high school health class? The ones that showed how a shot of liquor is equal to a beer, which is equal to a glass of wine?

Charts that show how many drinks it would take to reach different blood-alcohol concentrations vary, but most say two drinks would put a woman weighing 140 pounds or less over a 0.05 level. It takes men slightly more alcohol to reach that level but — crucially — those charts assume one “drink” is a small glass of wine containing 12 percent alcohol, or 1.25 ounces of 80-proof liquor, or a 12-ounce beer containing 4.5 percent alcohol.

Give that same woman a bottle of one of the high-alcohol craft beers available today, or an 8-ounce glass of California red zinfandel, and you could have a one-drink DUI under the proposed standard. For men weighing less than 180 pounds, it could take just two strong drinks.

“I think one drink with dinner is not going to put most Americans over 0.05,” Hersman said. “There are certainly questions, involving how much people weigh and whether they have food in their stomach.”

At the Charleston Beer Exchange, customers can find beers containing 9 percent alcohol, or more, which would count as two drinks on most blood-alcohol charts. Beers that strong are the exception, but it’s common to find craft beers with more than 6 percent alcohol, and some restaurants serve those beers by the pint.

Brandon Plyler, manager of the specialty beer shop, said he’s been seeing more restaurants start to vary their serving sizes to account for high-potency beer. A 9-percent alcohol double-IPA might be served in a 10-ounce glass, for example.

He noted that wine and liquor can also vary significantly, in terms of their potency.

“It’s not just beer,” Plyler said.

Fine to drive?

The American Beverage Institute, a restaurant trade group, says the 0.05 recommendation is “ludicrous.”

“Moving from 0.08 to 0.05 would criminalize perfectly responsible behavior,” said ABI Managing Director Sarah Longwell.

Restaurants would stand to lose lots of money if customers stopped at one drink, or didn’t drink at all, but restaurant trade groups aren’t alone in saying that 0.05 seems a bit too strict.

Charleston Police Chief Greg Mullen isn’t known for being soft on drinking — he cracked down on people carrying glasses of wine between art galleries during First Friday events — but Mullen was skeptical of lowering the standard.

“When you get down to 0.05 you could very easily find yourself over that limit and still be perfectly fine to operate a vehicle,” Mullen said. “The individuals we stop and do the Breathalyzer on are generally over the limit, and usually well above the 0.08.”

“I think that we are probably about where we should be,” he said. “I don’t think putting a 0.05 or 0.08 on it is going to change people’s behavior. I think we need to do a better job at educating, particularly young people, about the consequences.”

Most DUIs at 0.15+

Most drivers involved in fatal wrecks have either had nothing to drink, or have consumed enough alcohol to put them far over the current legal limit.

Nationwide, 64 percent of fatal crashes in 2011 involved no drivers with alcohol in their blood, and 31 percent involved at least one driver with a level high enough to be presumed impaired under current law. Most impaired drivers had at least triple the blood-alcohol limit the NTSB now endorses.

The remaining 5 percent of drivers in fatal wrecks had consumed alcohol, but not enough for most people to be presumed impaired under current laws. Underage drivers, commercial truck drivers and some others are held to tougher standards.

The members of the NTSB know that most fatal accidents involve people with either no alcohol or lots of it in their blood — those statistics came from the NTSB report calling for a lower tolerance for impaired driving. But the board said about 100 other nations including Ireland and Australia use a 0.05 or lower standard, and doing so in the United States could save lives.

“We do believe that lowering the (level) will have an overall deterrent effect,” Hersman said. “When we went from 0.10 to 0.08, overall alcohol consumption was reduced for all drinkers.”

In other words, today’s drunken drivers are less drunk than they used to be, but they are still involved in more than 30 percent of the nation’s fatal wrecks. The total number of fatal highway accidents has been falling steadily for years.

South Carolina has the nation’s highest rate of alcohol-impaired driving fatalities per miles driven, according to the National Highway Traffic Safety Administration. In 2011, 46 percent of South Carolina’s driving fatalities involved a driver who had consumed at least some alcohol, and 38 percent involved a driver with a level of .08 or more.

The NTSB recommendations call for a number of changes in enforcement, prosecution and education related to drinking and driving. Some recommendations are aimed at repeat offenders, others at changing attitudes.

The national Mothers Against Drunk Driving organization, which helped push the nation to reduce the threshold to 0.08 from the older standard of 0.10 more than two decades ago, has a legislative agenda of its own, which does not include further lowering the line.

“MADD is staying focused on its current initiatives,” said Carol Ronis in MADD’s national headquarters.

Ultimately, it will be up to individual states to decide whether to toughen the threshold. The NTSB is recommending that the federal government offer incentives.

“In many ways it’s about being a catalyst for a conversation that’s long overdue,” said NTSB Chairwoman Hersman. “It really is about what people are willing to tolerate when it comes to their safety and the safety of those around them.”

Reach David Slade at 937-5552.