Federal regulators recommended Tuesday that all states lower the blood-alcohol threshold for drunken driving from 0.08 to 0.05 percent, a proposal that was met with some skepticism in the hospitality industry and elsewhere in Maine.

The National Transportation Safety Board cited the continued high price of drunken driving, with 10,000 people on average dying every year and 173,000 injured in alcohol-involved crashes. The independent federal agency estimates that every day, 300,000 people get behind the wheel when they are impaired.

The NTSB said studies have shown that most drivers’ judgment and visual functions are impaired when their blood alcohol content is just 0.05 percent and they are more likely to be involved in crashes.

“Alcohol-impaired crashes are not accidents,” NTSB Chairman Deborah Hersman said in announcing the initiative. “They are crimes. They can — and should — be prevented. The tools exist. What is needed is the will.”

The NTSB made 10 recommendations, including that states require ignition locks to prevent people convicted of drunken driving from using their cars when drunk, and increasing high-visibility enforcement such as roadblocks.

But setting the limit so low, where the impact of alcohol is barely perceptible, could leave patrons unsure of whether they can have a glass of wine with dinner if they plan on driving home, said Dick Grotton, president and CEO of the Maine Restaurant Association.

“It’s an effort to prevent people from consuming alcohol altogether,” Grotton said. He thinks the decision was made without input from industries and people that might be affected by it.

Grotton said he believes there is virtually no impairment for most people at 0.05 percent, and that would leave police in a quandary about enforcing the law.Grotton expects it would be enforced primarily after there is a crash.

He also noted it would affect the hospitality and restaurant industry if people go out less.

Matthew Nichols of Portland, a criminal defense attorney who specializes in drunken driving cases, said he is not surprised by the recommendation but “they will be locking up a lot of innocent people.”

Nichols said he is familiar with the research that says some drivers start to be impaired at 0.05 percent blood alcohol. But there also are many drivers who could have the same level yet feel no effects, he said.

The rationale behind having set blood alcohol thresholds is to guard against people who may be able to mask the effects of alcohol, but whose reaction time might be slowed in an emergency, such as a child running into the street, Nichols said.

“It’s going to be a real challenge for law enforcement officers to make an arrest decision,” he said. “They’ve been trained for years to kind of gear these things toward .08. Now, if I’m a cop and a guy has a couple microbrews with high alcohol and he’s probably a .05, but he’s going to look fine to me, do I really want to arrest this guy? Is he really a danger on the road?”

Nichols believes a 0.05 level would require blood tests instead of breath tests to remove some of the small deviations that can occur between alcohol on the breath and in the blood.

Russ Rader of the Insurance Institute for Highway Safety said his organization has not analyzed the effect of lowering the drunken driving threshold because few states track those data.

“Crash risk is higher for drivers well-below .08″ than for drivers who have not been drinking, Rader said. “We would expect some effect if states lowered the blood alcohol content threshold to .05, but that’s difficult to quantify or estimate because no state has taken that step.

“One difficulty in the United States is enforcement. Impairment begins well before the classic signs of intoxication might become apparent to a police officer,” he said.

That may limit the impact of such a change. Police are required to have probable cause before they can pull a motorist over to administer a field sobriety test. That means they have to observe the motorist do something indicative of impairment, like crossing the center line or failing to turn on the headlights while driving at night.

The NTSB has no authority to impose its recommendation on states. However, the federal government has in the past threatened to withhold federal highway funds from states that do not adopt recommended safety standards.

The board’s announcement said more than 100 countries have blood alcohol limits of 0.05 percent or lower. Some countries have zero tolerance for drivers having alcohol in their system, and some countries ban alcohol altogether.

Maine established its drunken driving threshold in 1969. A level over 0.15 percent was intoxicated, and 0.10 to 0.15 was impaired.

The threshold was lowered to 0.10 in 1971 and to 0.08 in 1988.

Portland police Cmdr. Gary Rogers said it’s not unheard of for police to pull over someone on suspicion of drunken driving only to find the person’s blood alcohol content was less than 0.08. Often, that can be an indication that the impairment stems from drugs as well as alcohol.

But in some cases, it can be a person who is very susceptible to alcohol, he said.

“Some people may not be visibly impaired at .08 or .10, and then some people are visibly impaired at .06,” Rogers said.

Maine law already allows police to arrest and district attorneys to prosecute people whose blood alcohol content is 0.05 to 0.07. They are not presumed to be intoxicated based on the test result, but neither is that evidence they are not impaired, he said. If there is other evidence of impairment, such as failing a field sobriety test, a judge or jury can find the person guilty of drunken driving, Rogers said.

“With bar patrons, it may not change their lifestyle much,” Rogers said of the proposed change. “If they’re drinking several drinks, they should be taking a cab anyway” or have some other way of getting home safely.

“The ones the .05 would really have an effect on is the dinner crowd. It’s a lot easier to reach .05 at dinner than a .08,” he said.

Doug Fuss, owner of Bull Feeney’s in the Old Port and president of the Portland Downtown District’s board of directors, doesn’t object to a lower threshold, though he said it could be difficult to enforce.

“Lowering the threshold, if it’s going to save lives, then it’s a good thing,” he said. “The whole problem with legislating is you don’t want to get to the place where a law is so strict it’s difficult to enforce.”

The proposal got a mixed response at Shays grill pub, on Monument Square in Portland.

Kelly Boganwright thought it could leave small people in the lurch.

“Are they going to serve smaller beer?” she asked.

Her husband, Nick, said that in principle, it makes sense.

“You shouldn’t drink and drive anyway,” he said.

Megan Harmon disagreed with the recommendation.

“It’s great to keep people safe, but that’s two beers. They should keep it the same,” she said.

Mike Culcasi was skeptical of the motives behind the change.

“I think it’s a bad idea. I think it’s a way for them to raise revenue,” he said. “Two drinks and you’re in trouble.”

The anti-drunken driving group Mothers Against Drunk Driving, or MADD, gave the announcement a lukewarm reception. The group believes its own proposals would do more to reduce alcohol-related fatal crashes.

MADD wants people convicted of drunken driving to have to install an ignition lock, which prevents a car from starting if the driver has alcohol on the breath. The group also supports research into technology that would prevent drunken drivers from operating a vehicle. It backs high-visibility police roadblocks as well.

The group said lowering the drunken driving threshold is not a priority, suggesting it would not have as dramatic an effect on reducing fatalities.

David Hench can be contacted at 791-6327 or at:

dhench@mainetoday.com