Open Decision Ledger · Criminal & investigative procedure
Widmark calculation only marginally above the drink-driving limit
Supreme Court, July 18, 2025, 2024Do11906 (judgment)
No holding summary · checked against points at issue. The official text publishes no summary of the holding for this decision. The quotation and factors in this record are copied verbatim from the points at issue; the evidence for each axis is taken from the points at issue, the order and the reasons.
Case name: 교통사고처리특례법위반(치상)·도로교통법위반(음주운전)
Official text on the National Law Information Center
Question
Where it cannot be fixed whether the defendant drove while his blood alcohol concentration was rising or falling, the measurement was taken a considerable time after driving ended and the reading only slightly exceeds the limit, can the concentration at the time of driving be treated as proved to have exceeded 0.03%?
Holding
No. When the rising or falling phase cannot be fixed, a reading taken a considerable time after driving ended and only slightly above the limit does not establish that the concentration at the time of driving exceeded it. The premises of the Widmark formula must be strictly proved, and where uncertainty remains and tells against the defendant, the calculated result lacks probative force sufficient to exclude reasonable doubt; greater caution is required where the excess is only slight.
Points at issue, verbatim
피고인이 승용차를 운전할 당시 혈중알코올농도가 0.03% 이상의 술에 취한 상태였다는 사실이 합리적 의심을 배제할 정도로 증명된다고 보기 어렵다고 한 사례
Unofficial English translation
A case where it was held that the fact that the defendant was in a state of intoxication with a blood alcohol concentration of 0.03% or higher at the time he drove the passenger car cannot be regarded as having been proved to the extent of excluding reasonable doubt
Disposition
Reversed and remanded Stated in the decision
원심판결을 파기하고, 사건을 청주지방법원에 환송한다.
Unofficial English translation
The judgment of the court below is reversed, and the case is remanded to the Cheongju District Court.
Form of the test
Elements stated Stated in the decision
그 법칙 적용의 전제가 되는 개별적이고 구체적인 사실에 대하여는 엄격한 증명을 요한다 할 것이고
Unofficial English translation
strict proof is required for the individual and specific facts that form the basis for the application of that formula, and
Factors
- 음주운전 시점이 혈중알코올농도의 상승시점인지 하강시점인지 확정할 수 없는 상황에서
- 운전을 종료한 때로부터 상당한 시간이 경과하여 측정된 혈중알코올농도가 처벌기준치를 약간 넘은 경우
- 그 법칙 적용의 전제가 되는 개별적이고 구체적인 사실에 대한 증명의 정도
- 위드마크 공식에 의하여 산출한 혈중알코올농도가 법이 허용하는 혈중알코올농도를 근소하게 초과하는 정도인 경우
Unofficial English translation
• in circumstances where it cannot be determined whether the time of the drunk driving was on the ascending limb or the descending limb of the blood alcohol concentration
• where the blood alcohol concentration measured after a considerable time has elapsed from the time the driving was terminated only slightly exceeds the punishment threshold
• the degree of proof required for the individual and specific facts that form the basis for the application of that formula
• where the blood alcohol concentration calculated under the Widmark formula exceeds the blood alcohol concentration permitted by law only by a slight margin
Relation to precedent
Follows earlier decisions Stated in the decision
대법원 2013. 10. 24. 선고 2013도6285 판결(공2013하, 2175)
Unofficial English translation
Supreme Court Decision 2013Do6285 decided October 24, 2013 (Gong 2013 Ha, 2175)
Decisions referred to
[1] 대법원 2013. 10. 24. 선고 2013도6285 판결(공2013하, 2175) / [2] 대법원 2010. 6. 10. 선고 2009도10867 판결 / [3] 대법원 2001. 7. 13. 선고 2001도1929 판결(공2001하, 1904), 대법원 2003. 4. 25. 선고 2002도6762 판결(공2003하, 1383)
Burden of proof
The prosecution Stated in the decision
검사는, 피고인이 운전하기 전에 실제로 음주를 종료한 시점과 실제 음주량을 특정하고 이를 증명할 책임을 다하지 아니하였다
Unofficial English translation
the prosecutor failed to fulfill the responsibility of identifying and proving the time at which the defendant actually terminated drinking before driving and the actual amount of drinking
Open question and revisit condition
How far above 0.03% must the Widmark figure lie before the marginal-excess caution falls away and the strict proof of the premises is enough on its own?
The retrial judgment of the Cheongju District Court will show how the gap between the end of drinking, the end of driving and the measurement is treated on a fuller record. A later Supreme Court decision addressing the size of the margin above the standard, or an amendment to Article 44 or Article 148-2 of the Road Traffic Act, would require this entry to be read again.
Cross-family AI independent reading & axis check
5 of 8 axes matched GPT-6 Astra (OpenAI, codex CLI) · 2026-10-25
A reader from another model family (GPT-6 Astra), given the official text but not the primary reading, agreed on 5 of the 8 axes; the readings differed on axis 4 (form of the test), axis 7 (burden of proof), axis 8 (open question and revisit condition).
Axis 4 (Form of the test): Primary “Elements stated” vs Independent “Existing test applied”
The primary reads the court as stating the legal requirements for Widmark proof and the caution needed for a marginal excess, whereas the independent reads it as applying those requirements to the drinking facts of this case.
피고인이 승용차를 운전할 당시 혈중알코올농도가 0.03% 이상의 술에 취한 상태였다는 사실이 합리적 의심을 배제할 정도로 증명된다고 보기 어렵다고 한 사례Axis 7 (Burden of proof): Primary “The prosecution” vs Independent “Not addressed”
The primary names the prosecution as bearing the burden to prove the premises and resolve the uncertainty against the defendant, while the independent does not state who bears the burden and frames it only as reasonable doubt.
검사는, 피고인이 운전하기 전에 실제로 음주를 종료한 시점과 실제 음주량을 특정하고 이를 증명할 책임을 다하지 아니하였다Axis 8 (Open question and revisit condition): Primary “How far above 0.03% must the Widmark figure lie before the marginal-excess caution falls away and the strict proof of the premises is enough on its own?” vs Independent “What additional objective evidence would resolve the uncertainty about the earlier drinking sufficiently to establish the blood alcohol concentration at the time of driving?”
The primary asks how far above 0.03 percent the estimate must lie to drop the extra caution, while the independent asks what objective evidence about the earlier drinking would resolve the uncertainty.
피고인이 승용차를 운전할 당시 혈중알코올농도가 0.03% 이상의 술에 취한 상태였다는 사실이 합리적 의심을 배제할 정도로 증명된다고 보기 어렵다고 한 사례Raw responses and comparison record: Protocol · Blind readings (JSONL) · Axis comparison (JSONL) · SHA-256 (JSON)
Lower-court contrast & scope of application
Lower-court reading vs. Supreme Court holding
Lower-court context: The court below was the appellate judgment of the Cheongju District Court, to which the case returned after this remand. It found the drink-driving charge proved, taking the measured concentration of 0.277% at 01:37 on 19 June 2023 and deducting the rise attributable to the two bottles of soju drunk until about 01:15, giving estimates of 0.044%, 0.041% and 0.031% for additional drinking of 674㎖, 683㎖ and 710㎖, all above the 0.03% standard. It also reasoned that the first bout had ended by about 22:00 on 18 June 2023, so the rising phase was over, and on that basis convicted the defendant under the Road Traffic Act and, relying on it, under the Act on Special Cases in Handling Traffic Accidents (injury).
Supreme Court standard: The Supreme Court held that this could not stand. Because the defendant said the first bout ended by about 22:00 and the collision occurred 30 minutes later, the rising phase could not be excluded, and the prosecution had not discharged its burden of fixing and proving the actual end time and quantity of that drinking. The measurement came about 217 minutes after 22:00, so the back-calculation from the Widmark formula carried inherent uncertainty; even on the largest assumed additional intake of 710㎖ the figure was only 0.031%, a marginal excess. It reversed the whole judgment and remanded the case to the Cheongju District Court, on the unanimous opinion of the Justices, without ruling on the other grounds of appeal.
Distinguishing conditions
- A case in which objective material, such as receipts or a test of a specimen taken soon after driving, fixes when the drinking ended and how much was drunk, so that the phase at the time of driving can be determined.
- A case in which the Widmark back-calculation yields a figure that exceeds the 0.03% standard by a wide margin rather than only slightly, since the Court reserved its greater caution for a marginal excess.
- A case in which the rise attributable to later drinking is itself established to a certainty, so that no uncertainty remains in the back-calculation.
Record verification notes
Set the time of the end of driving against the time of the measurement and against the 30 to 90 minute window in which the concentration is said to peak, since the Court relied on a gap of about 217 minutes and a 30 minute gap. Then run the back-calculation across the whole plausible range of later intake, not one figure, and record how close the lowest result sits to the 0.03% standard. Finally, check whether the prosecution fixed the end time and quantity of the earlier drinking by objective material rather than by the defendant's own statement alone.
From the official text
Points at issue
[1] 음주운전 시점이 혈중알코올농도의 상승시점인지 하강시점인지 확정할 수 없는 상황에서 운전을 종료한 때로부터 상당한 시간이 경과하여 측정된 혈중알코올농도가 처벌기준치를 약간 넘은 경우, 실제 운전 시점의 혈중알코올농도가 처벌기준치를 초과하였다고 단정할 수 있는지 여부(소극) [2] 위드마크 공식을 사용하여 운전 당시 혈중알코올농도를 추정하는 경우, 그 법칙 적용의 전제가 되는 개별적이고 구체적인 사실에 대한 증명의 정도 [3] 위드마크 공식에 의하여 산출한 혈중알코올농도가 법이 허용하는 혈중알코올농도를 근소하게 초과하는 정도인 경우, 위 공식에 의하여 산출된 수치에 따라 범죄의 구성요건 사실을 인정함에 있어서 더욱 신중하게 판단하여야 하는지 여부(적극) [4] 피고인이 1차 음주 이후 2023. 6. 18. 22:30경 차량을 운전하다가 신호대기 정차 중이던 차량을 충격한 후 2023. 6. 19. 01:15경까지 편의점에서 소주 2병을 구매한 뒤 거의 마셨고, 경찰관이 2023. 6. 19. 01:37경 피고인에게 음주측정을 실시한 결과 혈중알코올농도가 0.277%로 측정되었는데, 피고인이 경찰에서 1차 음주시간을 2023. 6. 18. 22:00경까지라고 진술한 것 외에 피고인의 음주 시작 및 종료 시각과 음주량을 확인할 수 있는 구체적이고 객관적인 자료가 없는 상황에서 ‘혈중알코올농도 0.03% 이상의 술에 취한 상태로 승용차를 운전하였다.’는 내용으로 기소된 사안에서, 피고인이 승용차를 운전할 당시 혈중알코올농도가 0.03% 이상의 술에 취한 상태였다는 사실이 합리적 의심을 배제할 정도로 증명된다고 보기 어렵다고 한 사례
Unofficial English translation
[1] Where, in circumstances where it cannot be determined whether the time of the drunk driving was on the ascending limb or the descending limb of the blood alcohol concentration, the blood alcohol concentration measured after a considerable time has elapsed from the time the driving was terminated only slightly exceeds the punishment threshold, whether it can be conclusively determined that the blood alcohol concentration at the time of the actual driving exceeded the punishment threshold (negative) [2] Where the blood alcohol concentration at the time of driving is estimated using the Widmark formula, the degree of proof required for the individual and specific facts that form the basis for the application of that formula [3] Where the blood alcohol concentration calculated under the Widmark formula exceeds the blood alcohol concentration permitted by law only by a slight margin, whether the constituent elements of the crime must be determined with greater caution based on the figure calculated under that formula (affirmative) [4] A case where, in a case prosecuted on the charge that "he drove a passenger car while in a state of intoxication with a blood alcohol concentration of 0.03% or higher," in which the defendant, after a first round of drinking, drove a vehicle at approximately 22:30 on June 18, 2023, struck a vehicle that was stopped waiting for a traffic signal, and thereafter purchased 2 bottles of soju at a convenience store and drank almost all of them by approximately 01:15 on June 19, 2023; a police officer conducted an alcohol test on the defendant at approximately 01:37 on June 19, 2023, and the blood alcohol concentration was measured at 0.277%; and in circumstances where, other than the defendant's statement to the police that the time of his first drinking ended at approximately 22:00 on June 18, 2023, there was no specific and objective material by which the times at which the defendant began and ended drinking and the amount of drinking could be verified, it was held that the fact that the defendant was in a state of intoxication with a blood alcohol concentration of 0.03% or higher at the time he drove the passenger car cannot be regarded as having been proved to the extent of excluding reasonable doubt
Summary of the holding
The official text publishes no summary of the holding for this decision. The quotation and factors in this record are copied verbatim from the points at issue; the evidence for each axis is taken from the points at issue, the order and the reasons.
Order
원심판결을 파기하고, 사건을 청주지방법원에 환송한다.
Unofficial English translation
The judgment of the court below is reversed, and the case is remanded to the Cheongju District Court.
Provisions referred to
[1] 도로교통법 제44조, 제148조의2, 형사소송법 제307조 [2] 도로교통법 제44조, 제148조의2, 형사소송법 제307조 [3] 도로교통법 제44조, 제148조의2, 형사소송법 제307조 [4] 도로교통법 제44조, 제148조의2, 형사소송법 제307조, 형사소송법 제325조
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