By KELLY HANNON

Concentrating her gaze on the white strip of tape on the floor in front of her, Kim Brittain stuck out her foot.

"One," she said, placing her foot heel-to-toe on the tape. "Two," she said, taking another step. "Three. Four. Five. Six."

Brittain bobbled slightly, and raised her arms an inch or two to steady herself. "Seven. Eight. Nine."

She swiveled, preparing to take another nine steps back to her starting point.

The turn wasn't smooth.

Around her, six law enforcement officers started scribbling on forms.

Fortunately for Brittain, she's not in any trouble.

Brittain was taking a field sobriety test in a training room at the Rappahannock Regional Criminal Justice Academy in Fredericksburg. If she had been driving a car, she would've been arrested.

A retired Detroit Police Department officer living nearby, Brittain volunteered to help the Virginia Department of Motor Vehicles train Fredericksburg-area law enforcement officers to administer sobriety tests.

Brittain gave such tests countless times in her 22- year career. But Thursday was her first time taking it while intoxicated.

It did not go well.

Brittain's eyes betrayed her during a test for nystagmus, the involuntary jerking of the eyes. An officer moving a pen back and forth in front of her eyes picked up on it, and later noticed her trembling and losing her balance during a one-leg stand where drivers must also count "one thousand and one, one thousand and two, one thousand and three " for up to 30 seconds, all while staring at their leg. "That's difficult to do," Brittain said. Even sober, she added.

learning the limits

She sipped five mixed drinks--all vodka and orange juice--over a two-hour period Thursday morning at the training center before her test. Each drink had 11/2 ounces of vodka, measured carefully by the DMV trainers, who control the volunteers' intake, periodically giving Breathalyzer tests.

"After the first one I felt like there was no way I could drive," said Brittain, who had two pieces of toast for breakfast. She was amazed that it took five drinks for her to reach the legal limit for drivers in Virginia, a blood alcohol content of 0.08 percent--far more than she would ever drink personally, she said.