Topeka ? The Kansas Supreme Court on Friday overturned the DUI conviction of a Wichita man in a case that could make it more difficult for law enforcement to show they have probable cause to believe a driver is intoxicated.

William J. Molitor was arrested in 2009 during a saturation patrol by Wichita police around a local bar. He was pulled over for failing to signal a right-hand turn, although records showed he turned correctly and was driving straight. When he was pulled over, he reportedly ran the right front wheel of the car halfway up the curb.

The arresting officer testified that Molitor and his car smelled of alcohol. He administered all three of the “standardized field sobriety tests,” starting with one that has never been admissible as evidence in Kansas courts, the horizontal gaze nystagmus, or HGN test.

That’s a test in which an officer looks for horizontal jerking or bouncing of the eye when it’s turned to the side.

Records showed Molitor failed that test but passed the two other standard tests involving walking and turning, and standing on one leg. But based on his failing score on the HGN test, the officer administered a preliminary breath test, which registered .09 percent blood alcohol, slightly above the legal limit of .08 percent.

Molitor argued that police had no probable cause to ask him to submit to a breath test because the HGN test is inadmissible as evidence in Kansas courts. But the trial judge said it could still be used to support probable cause to believe someone might be intoxicated, and thus justify administering the breath test.

In a 4-3 ruling, the Supreme Court overturned the conviction and remanded the case back to Sedgwick County, saying the HGN test could not be used, and the fact that Molitor passed the other two sobriety tests meant there was not probable cause to support asking for a breath test.

Justice Dan Biles agreed that the HGN test should not have been used, but said in a separate opinion that there was enough other evidence and that the conviction should have been upheld.