Politics · South Korea · 3 hrs ago
South Korea Supreme Court Rejects Breath Test Evidence in DUI Case
South Korea's Supreme Court overturned a drink-driving conviction based on a breath test after police failed to give the driver water to rinse his mouth.
The case involved a truck driver found asleep in his running vehicle on a road in Sejong in December 2023.
Police measured his blood alcohol level at 0.081%, and prosecutors also cited a 2019 drink-driving offence.
Lower courts upheld a sentence of one year in prison, suspended for two years, but the Supreme Court said the test result could not be used as evidence of guilt.
Since July 2023, a rule in South Korea's Road Traffic Act enforcement regulations has required police to provide water before testing, the court said.
It also said residual alcohol in the mouth could still affect a test, even after 20 minutes, and sent the case back to Daejeon District Court.
South Korea’s Supreme Court overturned a DUI conviction after police failed to provide water for the driver to rinse his mouth before a breath test.
The court ruled that the test result could not be used as evidence because the mouth-rinsing procedure was legally binding.
The driver had been found asleep in a truck on a road in Sejong in December 2023, with the engine running.
The lower courts had sentenced him to one year in prison, suspended for two years.
The case was sent back to the Daejeon District Court.
- Who
- The Supreme Court and a driver identified as A.
- What
- The court overturned the driver’s conviction, ruling that the breath-test result could not be used as evidence.
- When
- The ruling was issued recently, according to an article published on October 25, 2026. The incident took place in December 2023.
- Where
- The incident took place on a road in Sejong, South Korea. The case was returned to the Daejeon District Court.
- Why
- Police did not provide water for the driver to rinse his mouth before testing, despite a legally binding procedure requiring it.
Lower courts
Supreme Court
Breath-test evidence
Lower courts
The lower courts considered the test result sufficiently reliable and allowed it to support a conviction.
Supreme Court
The Supreme Court ruled that the result was inadmissible because police did not follow the legally binding procedure.
Need for mouth-rinsing water
Lower courts
The lower courts said the failure to provide water did not make the test unlawful; the appeals court also said the driver was responsible because he began the test suddenly.
Supreme Court
The Supreme Court held that the required procedure had legal force and had not been followed.
The procedure for providing water to rinse the mouth was written into South Korea’s Road Traffic Act Enforcement Rules.
A driver was found asleep in a running truck on a road in Sejong and was given a breath test.
The court sentenced the driver to one year in prison, suspended for two years.
The appeals court upheld the first-trial ruling and dismissed the driver’s appeal.
The Supreme Court overturned the ruling and sent the case back to the Daejeon District Court.
- Breath-test result
- 0.081% blood alcohol concentration
- Driver’s sentence
- One year in prison, suspended for two years
- Earlier DUI case
- A 2019 DUI resulted in a 1 million won summary fine
- Relevant rule
- Mouth-rinsing water procedure added to enforcement rules in July 2023
- Case destination
- Daejeon District Court
1 source
What people are saying
In actual DUI enforcement settings, it cannot be said that the risk of residual alcohol causing the blood alcohol concentration to be measured higher than it actually is disappears.
The defendant suddenly got up, put his mouth on the device and blew, so the responsibility for not providing drinking water lies with the defendant.