Stuart Miller, arrested in July along with Washington Redskins running back John Riggins on alcohol-related offenses, was found not guilty yesterday of driving while intoxicated after he claimed his cowboy boots made him lose his balance during a sobriety test.

"I did that sobriety test fairly well, but was losing my balance because of my boots," Miller testified yesterday as his attorney, Jerry M. Phillips, held up one of the alligator boots in the General District Courtroom in Fairfax.

"When I stood on one foot I could feel myself slipping."

Miller, 40, co-owner of Dixie Liquors in Georgetown, was driving Riggins home at about 1:50 a.m. on July 25 when his car was pulled over by a Fairfax County police officer in Reston. Miller was charged with DWI; Riggins, 35, was charged with being drunk in public.

Riggins is scheduled to appear in court on Oct. 24. Miller said yesterday outside the courthouse that Riggins was not drunk in public. "He was basically very mild mannered," he said. "I don't know what was going through the officer's mind."

Officer T.W. Field testified in the nonjury trial yesterday that when he administered one of three field sobriety tests he gave Miller, which required him to stand on one foot and count from 1,001 to 1,025, Miller's eyes were bloodshot, he was unsteady on his feet and he "had to put his hand against his BMW five times to keep himself from falling."

The officer also testified that Miller unsuccessfully performed a heel-to-toe walking test and skipped a letter when asked to recite the alphabet.

But Phillips held up the cowboy boot in court yesterday and said it was the reason his client had difficulty with the test. "He probably had two of them on?" Judge Steward P. Davis asked, nodding at the boot.

Phillips also argued that leaving out a letter of the alphabet did not prove Miller was drinking excessively and that a blood alcohol test taken after his arrest showed an alcohol content of 0.09 percent. In Virginia, 0.10 and above is the standard to determine whether someone is legally drunk.

Assistant Commonwealth's Attorney Raymond F. Morrogh, who prosecuted the case, said in closing arguments that Miller never mentioned to the police officer that he was having difficulty with the test because of his cowboy boots. "It's easy to Monday-morning quarterback," he said.

Morrogh also maintained that Miller did not lower the beam on his headlights when the officer flicked his lights at him along Sunrise Valley Drive before his arrest, and that Miller made a left turn onto Reston Avenue from a right-hand lane -- what Morrogh called "errors in judgment" -- because he was under the influence of six and possibly seven beers.

But Miller had testified that he was lost. He said that after he and Riggins had drinks at Clyde's at Tysons Corner with friend Jane Mundy, they had gone to the American Cafe to dance, then went back to Clyde's and finally stopped for omelets at a restaurant along Rte. 123 before heading home.

"John said he wanted to try a shortcut," Miller testified. But he said they got lost and, when they got to Reston Avenue, Riggins said: "No, looks like we're going to have to go left." At that point, Miller said, he turned left from the right-hand lane.

Mundy, another friend, a bartender from Clyde's and a maitre d' from the restaurant testified for the defense that they did not notice anything unusual about Miller that night.

Had Miller been convicted, he could have received a maximum $1,000 fine and up to a year in jail. For being drunk in public, the fine is $100. Both charges are misdemeanors.