Experiments show how much alcohol impairs diners

WILMINGTON- Over the last several winters, local restaurateurs and bar owners have complained that traffic enforcement efforts in the village have stifled their business. Locals and visitors alike, they say, are staying home because they feel they can’t enjoy a drink or two with their dinner without risking a traffic stop and a charge of driving under the influence.

This week the Wilmington Police Department held a “controlled drinking experiment” at a local restaurant to dispel the notion that two – or even three – drinks over the course of a dinner will land anyone in trouble with the law. Five volunteers, weighing from 110 pounds to 205 pounds, were given two drinks over the course of an hour. Some of the volunteers drank 12-ounce bottled beer, others had mixed drinks, and one drank wine for the experiment. Each of the volunteers started off with a field dexterity test and an alcosensor test to set a baseline before consuming any alcohol.

During the field dexterity tests by Wilmington police, volunteers were asked to walk a straight line heel-to-toe, pivot on one foot, and walk heel-to-toe back to the starting point. Another test required volunteers to raise one foot off the ground with their leg extended in front of them, while counting for 30 seconds. Wilmington Police Chief Joe Szarejko says police are looking for clues such as an inability to follow officers’ instructions, or an outright inability to perform the actions.

Police also administered a “horizontal gaze nystagmus” test in which volunteers were instructed to follow the tip of a pen or a finger while the testing officer moved it from one side of their field of vision to the other. Nystagmus is an involuntary bouncing of the eye that occurs as the result of the brain’s inability to control eye muscles while under the influence of alcohol or other depressants. Like other field sobriety tests, the inability to control the eye muscles becomes more pronounced with greater impairment. Wilmington police use the HGN test as an assessment tool, and to develop probable cause if an officer suspects a driver is under the influence.

Volunteers in Szarejko’s demonstration took the field sobriety tests after each drink, and after two drinks were consumed in the first hour, each of the volunteers was tested with the department’s electrochemical fuel-cell alcohol breath analyzer.

After two drinks, none of the volunteers were over the legal blood alcohol limit of 0.08. The highest level, obtained from the wine drinker, was 0.059. But the others ranged from a low of 0.014 to a mean of about 0.03. One of the volunteers, a 110-pound woman, registered 0.028 after two mixed drinks.

The official test results were reflected in the results of field sobriety testing. None of the volunteers failed the manual dexterity or HGN tests.

“People may know someone that says they got a DUI after having a couple drinks with dinner,” Szarejko says. “But it just isn’t true, and I think this shows it.”

Three of the volunteers continued the experiment, consuming one more drink and bringing their total consumption to three drinks in about an hour and a half. After passing another round of field sobriety testing, their blood alcohol levels were measured again – this time with results ranging from just 0.02 to 0.044.

Although all the volunteers were provided with transportation, had they been stopped for a traffic violation, Szarejko said, they might have been asked to perform the field sobriety tests, but they wouldn’t have been charged with a DUI even if they failed the field testing. “If they failed the field dexterity exercise and were weaving on the road, the officer probably wouldn’t let them drive home,” Szarejko says. “If they were a 0.03 and seemed okay to drive, the officer would probably let them go. That’s a decision the officer has to make based on experience and what he’s observed.”

Szarejko says it’s not the people who are having a drink or two with dinner that are getting arrested for DUI. The average blood alcohol level of those charged with DUI in Wilmington is 0.137 – well over the limit, and almost certainly the result of more than “a couple” of drinks. “To have a blood alcohol level of 0.137, a 150-pound male would have to have about five drinks in an hour, or six in an hour and a half,” Szarejko estimates.

But Szarejko said the department doesn’t advocate drinking any alcohol and driving. “We always advocate that someone who hasn’t been drinking do the driving,” he says. “But if the average dinner is an hour and a half, it’s safe to have a couple of drinks.”