Police, scientists squaring off over field sobriety tests

November 20, 2005

Stand up!

Heels together. Toes out. Hands at your sides. Raise the leg of your choice in front of you, 6 inches off the ground, leg straight, toe pointed. Keep your eyes on your raised toe and begin counting aloud from 1,001 until I say stop.

One thousand one. One thousand two ...

Some dark night on the side of the road, police car lights flashing in your peripheral vision, your freedom might depend on how well you do this.

Did you sway? Raise your arms for balance? Hop, or put your foot down? If you did any two, an officer will conclude with 65 percent accuracy, as stipulated in the prevailing science of inebriation diagnostics, that you might be too drunk to drive.

Did you bend your leg? Stare straight ahead instead of at your foot? Begin too soon? Officers are taught that people under the influence of alcohol don't follow directions well.

This is the one-leg stand -- OLS in cop-speak. It is one of the three scientifically researched standardized field sobriety tests, blessed by the National Highway Traffic Safety Administration, that officers call "the Holy Grail" and give on the roadside to help them decide whether to make an arrest for drunken driving.

The NHTSA says officers using scores from all three tests will be 91 percent accurate in making an arrest.

The NHTSA says the most accurate of the three is the horizontal gaze nystagmus test, or "jerking eyeball" test. An officer holds a penlight or small flashlight before you and asks you to track it visually from side to side. If you've indulged too much, your eyeballs will begin shaking about 45 degrees from the center.

The two other tests, the one-leg stand and the walk and turn (nine steps forward and back on a straight line), are "divided attention" tests that require both mental concentration and physical coordination. The one-leg stand has its skeptics and its court challenges, but the test is "easily performed by most unimpaired people," the NHTSA says.

Before the one-leg stand, police officers were on their own.

Some threw coins on the ground and ordered that only nickels or quarters be picked up. They would have a driver lean back and touch one finger to his nose. Recite the alphabet without singing. Count backward from 100 by threes. Trace a paper maze. Rapidly tap a telegraph key. Some gave tongue twisters such as "Methodist, Episcopal, sophisticated statistics." Texas Rangers just chatted for a bit before making a judgment call.

Chuck Hayes, a state trooper for 30 years in Oregon, remembers fellow officers putting their flashlights on the ground and telling drivers to run around them five times.

"How are you going to tell if a person is impaired that way?" said Hayes, now a field sobriety test trainer for the International Association of Chiefs of Police. "There was just some weird, weird stuff."

So in 1975, the NHTSA requested proposals to develop a valid, standardized test battery that would be easy to use on the side of the road. Marcelline Burns and her colleagues at the nonprofit Southern California Research Institute in Los Angeles got the job.

Burns, 77, is a research psychologist who calls herself the "grandma guru" of the standardized field sobriety tests. She's had a long career developing them, testifying in courts nationwide as an expert witness and training police officers to use them correctly.

Her group recruited 238 subjects from the local unemployment office -- anyone over age 21 with a driver's license and who admitted to imbibing a few -- and paid them $3 a day. Subjects came to the lab, starting at 8 a.m., and were "dosed" with either a placebo of orange juice or a screwdriver. They were then led to small rooms where 10 California police officers waited. The officers administered six sobriety tests, then made a determination on the subject's blood-alcohol content and whether they would make an arrest.

Burns' final report, "Psychophysical Tests for DWI Arrest," was published in 1977. She wrote that while all six tests were sensitive to alcohol -- meaning that drunken subjects tended to perform worse than sober ones -- the "best" tests were the three now in use today.

Burns did not test the drunken subjects when sober to see how well they could balance on one leg naturally.

"The evidence that it's an easy task comes from the placebo people," she said. "They could do it fine."

Here's a bar chart from her study: Most were men, ages 22 to 29.

One could argue the placebo people didn't look much like America.

So hundreds of thousands of drivers have been arrested -- no doubt many deservedly so -- on the basis of a 30-year-old study that, critics argue, has never been published in a peer-reviewed, scientific journal, never tested on a large scale with a control group and, perhaps more astonishing, has nothing to do with actual impairment from alcohol. Burns admits upfront that the tests are designed only to gauge blood-alcohol content, not whether you're a menace on the road.

Burns insists that the average person should be able to balance on one leg for 30 seconds. She can. She practices the one-leg stand every few weeks.

Question of balance

Consider how imbalanced we are. Forty percent of Americans will at some point in their lifetime experience a balance disorder, and dizziness and vertigo are the third leading cause of doctor visits, behind lower back pain and headaches, according to the National Institutes of Health.

Research indicates that the older you get, starting about age 50, the less likely you will be able to stand on one leg for very long, and the more likely you will be to fall. It's anybody's guess as to the "normal" ability to balance.

"The human equilibrium is a very complex system," said Richard Gans, founder and director of the American Institute of Balance in Florida. "Some people refer to it as the sixth sense, and that doesn't mean I see dead people.'"

The body must use three different systems to balance: The vestibular system that works like "finely tuned gyroscopes" in each inner ear, the visual system and the skeletal system, particularly the muscles, joints and tendons in the lower half of the body.

Ever had encephalitis, meningitis, shingles, chickenpox, ear infections, cardiovascular problems, numbness or tingling in the extremities, or migraines? You may be unable to balance. Diabetes? You may not be able to feel your feet well enough to balance.

Alternatives

Some forensic psychologists and a slew of DWI defense attorneys have been assiduously picking apart Burns' research on the standardized field sobriety tests for years. She is unmoved.

"We're now 30 years past the development of the test. They're widely used by police officers. Why would they use them if they don't help them make a proper decision?" she said. "These defense attorneys write all this stuff, but never once do they suggest an optional test. What do they want the officer to do? Toss a coin?"

Not at all, says Spurgeon Cole, a Georgia forensic scientist and consultant who has been Burns' chief nemesis in court and expert witness for the defense for years. But maybe videotapes in patrol cars, he argues, would help remove some of the subjectivity.

"How does age or gender affect performance? How does fatigue or practice affect performance?" he has written. "Without answers to these basic questions, the SFST remain in the same category as tarot cards."

Cole administered the tests to 21 of his students at Clemson University in South Carolina -- none of whom had had a drop of alcohol -- and showed the videotape of their performance to a group of officers, who reported they'd arrest nearly half the students.

"And these people had absolutely zero to drink," Cole said in an interview. "These tests are absolutely worthless."

So what's a police officer to do?

Some researchers like the "alternating hand pat" test, in which the subject hits the back of one hand with the palm of the other and then alternates hands. Others believe some kind of driving simulator would be best. A closed driving course, while impractical, would be best, everyone agrees. But previous studies have found that about 20 percent of drivers actually improve with alcohol. "I guess it calms them down," Cole said.

That leaves us right back where we started, with the one-leg stand.

One thousand one. One thousand two. One thousand three...