A breath-test result cannot be used as evidence of guilt if police failed to give a driver water to rinse out their mouth before the test, the Supreme Court has ruled. Providing rinsing water is a procedural duty written into law, the court said, so a reading obtained in violation of that duty amounts to illegally gathered evidence.
The Supreme Court's First Division, with Justice Chun Dae-yeop as the presiding justice, recently overturned a lower court ruling that had sentenced a defendant identified as A to one year in prison, suspended for two years, on charges of violating the Road Traffic Act through drunk driving, legal sources said on the 25th. The case was sent back to the Daejeon District Court.
A was indicted on charges of driving while intoxicated along about a 3-kilometer stretch of road in Sejong on Dec. 9, 2023. Police responded to a report that a driver was asleep in a car with the engine running in the middle of the road and arrested A. Officers then administered a breath test at a local police substation without providing water to rinse the mouth, and A's blood alcohol level registered at 0.081%. A's side challenged the admissibility of the result, arguing that alcohol remaining in the mouth may have pushed the reading above the actual level. Article 27-2 of the Enforcement Rules of the Road Traffic Act, in effect since July 4, 2023, requires police to provide drinking water so that a driver can rinse away residual alcohol in the mouth before a breath test.
The trial court and the appellate court rejected A's argument, saying it could not be concluded that the result was inaccurate simply because no rinsing water was provided. The trial court held that providing rinsing water was merely a procedure under internal police guidelines, with no binding effect on outside parties. The appellate court found that A was responsible for the fact that the water could not be provided.
The Supreme Court took a different view and refused to recognize the breath-test result as admissible evidence. Unlike internal police guidelines, the court said, the Enforcement Rules provision requiring drinking water to rinse away residual alcohol before a breath test is a legal order with binding effect on outside parties. Police must provide the water and instruct and encourage the driver to rinse the mouth thoroughly, the court said. It also ruled that the procedure cannot be skipped merely because the driver was asleep.
The court further said that even more than 20 minutes after drinking, the possibility cannot be ruled out that alcohol remaining in the mouth from burping or vomiting could push the reading higher.