Drunk Driving with "Difficulty in Normal Driving": What Subjective Awareness is Needed for Japan's Dangerous Driving Offense?

Impaired driving, whether due to alcohol or drugs, poses a grave threat to public safety, and legal systems worldwide have implemented stringent measures to combat it. In Japan, beyond standard DUI offenses, a more serious crime known as "Dangerous Driving Causing Death or Injury" (危険運転致死傷罪 - kiken unten chishishōzai) targets specific high-risk driving behaviors that result in casualties. One category of this offense involves driving under the influence of alcohol or drugs to an extent that "normal driving is difficult."

Crucially, a conviction for this serious offense requires not only objective proof of such impairment but also a specific subjective awareness on the part of the driver regarding their compromised state. This article delves into this critical subjective element, exploring how Japanese law defines and proves the driver's recognition that they were in a condition where normal driving was difficult, with a focus on a key High Court decision involving "dangerous drugs."

The Offense of Dangerous Driving Causing Death or Injury (Impairment Type)

The legal provisions for Dangerous Driving Causing Death or Injury were initially introduced into Japan's Penal Code (Article 208-2) and have since been refined and are now primarily housed within the "Act on Punishment of Acts Causing Death or Injury by Driving a Motor Vehicle, etc." (自動車の運転により人を死傷させる行為等の処罰に関する法律 - Jidōsha no Unten ni yori Hito o Shishō Saseru Kōi-tō no Shobatsu ni Kansuru Hōritsu), often abbreviated as the 自動車運転死傷行為処罰法 (Jidōsha Unten Shishō Kōi Shobatsu Hō).

Article 2, item 1 of this Act specifically addresses driving under the influence of alcohol or drugs. For this provision to apply, several elements must be established:

1. Driving under the influence of alcohol or drugs.
2. This influence must cause a state where "normal driving is difficult" (正常な運転が困難な状態 - seijō na unten ga konnan na jōtai). This refers to a significant impairment of the physical or mental skills essential for safe vehicle operation, such as perception, judgment, and motor control. It implies a level of incapacitation more severe than that required for a standard DUI (酒気帯び運転 - shukiobi unten). The Supreme Court of Japan, in a decision dated October 31, 2011 (Saikō Saibansho Kettei, Heisei 23-nen 10-gatsu 31-nichi, Keishū 65-kan 7-gō 1138-ページ), clarified that this state involves difficulty in conducting driving operations according to the road and traffic conditions.
3. The act of driving in such a state must cause the death or injury of another person.
4. Subjective Awareness (the focus of this article): The driver must have recognized or been aware that, due to the influence of alcohol or drugs, they were currently in a state where normal driving was difficult.

This subjective element is critical. It is not merely about proving the driver knew they had consumed alcohol or drugs, nor is it about proving they intended to cause an accident or harm. Rather, the prosecution must establish that the driver possessed a conscious awareness—even if in the form of dolus eventualis (未必の故意 - mihitsu no koi, i.e., recognizing a significant risk and proceeding anyway)—of their present, actual impaired state and its direct impact on their ability to drive normally. This heightened subjective requirement distinguishes this grave offense from ordinary negligent driving causing death or injury (過失運転致死傷罪 - kashitsu unten chishishōzai).

Proving Subjective Awareness: A Key Evidentiary Challenge

Establishing this specific subjective awareness—the driver's internal recognition of their difficulty in normal driving—can be one of the most challenging aspects for prosecutors, especially if the driver denies such awareness, claims amnesia, or offers alternative explanations for their driving behavior. Courts must therefore infer this mental state from a range of circumstantial evidence.

Key Case: Driving Under the Influence of "Dangerous Drugs" (Osaka High Court Decision, April 17, 2013)

The Osaka High Court decision of April 17, 2013 (Ōsaka Kōtō Saibansho Hanketsu, Heisei 25-nen 4-gatsu 17-nichi, published via Hanrei Hisho) provides a significant illustration of how Japanese courts approach the proof of this subjective element, particularly in the context of impairment by substances other than alcohol, such as "dangerous drugs" (危険ドラッグ - kiken doraggu), a term used in Japan for psychoactive substances often designed to mimic illegal drugs but not yet formally controlled (formerly also known as 脱法ハーブ - dappō hābu, "loophole herbs").

Factual Background

The defendant in this case drove a vehicle after inhaling "dangerous drugs." While driving, he experienced significant psychoactive effects, including altered consciousness, potential hallucinations, and a loss of normal awareness. His driving became erratic; he suddenly and inexplicably accelerated, leading to a series of rear-end collisions with another vehicle, which resulted in injury to the driver of that vehicle.

The objective fact of his impairment—that he was in a state where normal driving was difficult due to the drugs—was not substantially disputed. The core of the defense argument, however, was that the defendant was not subjectively aware at the time of driving that he was in such a compromised state. He argued that he therefore lacked the specific subjective recognition required for a conviction under the Dangerous Driving Causing Injury statute.

Rulings of the First Instance and High Courts

• Kyoto District Court (First Instance - December 6, 2012): The District Court found that the subjective awareness requirement was met and convicted the defendant. The court's inference of this awareness was based heavily on the defendant's history and experiences prior to the incident in question:Based on this pattern of prior experience, self-acknowledged risk, and external warnings, the District Court concluded that the defendant, when he chose to use the drugs immediately before driving on this occasion, was acutely aware of the high probability that doing so would once again render him incapable of normal driving.
  1. Habitual Use and Prior Impairments: The defendant was a habitual user of these types of "dangerous drugs." Critically, he had experienced significant episodes of impairment from these drugs on previous occasions. These episodes included instances of "freezing" or losing awareness for short periods, sometimes even while driving. Past driving incidents attributed to his drug use included veering into oncoming traffic and making sudden, unnecessary stops, after which he reportedly admitted to "spacing out" (固まってて - katamattete), or having no memory of the event.
  2. Self-Acknowledged Risks: The defendant had previously made statements acknowledging the dangers associated with his drug-impaired driving, such as, "I could crash at any time."
  3. Warnings from Others: He had received explicit warnings from his romantic partner and others regarding the perils of his using these drugs before or while operating a vehicle.
• Osaka High Court (Appeal - April 17, 2013): The Osaka High Court affirmed the District Court's conviction, specifically upholding its finding on the subjective element of awareness. The High Court's reasoning mirrored and reinforced that of the first instance court:
  1. Reiteration of Prior Impaired Driving Episodes: The High Court emphasized the defendant's multiple past experiences where his use of "dangerous drugs" directly led to an inability to drive normally.
  2. Heightened Awareness of General Risks: The court also noted an interesting piece of evidence: shortly before the incident, the defendant had reportedly been discussing news reports about traffic accidents caused by "dangerous drug" use with his wife (during which he denied his own current use). This indicated a general, and perhaps even heightened, awareness of the specific risks associated with such substances and driving.
  3. Inference of Subjective Recognition: Synthesizing these points, the High Court concluded that the defendant, when he made the decision to drive after consuming the "dangerous drugs" on this particular occasion, did so while fully recognizing the substantial likelihood—if not certainty—that the drugs would again precipitate a state where his normal driving ability would be severely compromised. This level of awareness, the court found, satisfied the subjective requirement for the offense of Dangerous Driving Causing Injury.

Significance of the Osaka High Court Case

This 2013 Osaka High Court decision is instructive for several reasons:

• Proof of Awareness Through Prior Conduct: It clearly demonstrates that the necessary subjective awareness of being in a state of "difficulty in normal driving" can be robustly inferred from a consistent pattern of prior similar experiences with the impairing substance, especially when those experiences directly involved compromised driving ability.
• Cumulative Effect of Knowledge: The case shows that various sources of knowledge can contribute to establishing this awareness: personal experience of impairment, explicit warnings from others, and even general knowledge of the dangers (such as from news reports), particularly when it resonates with the individual's own past experiences.
• Focus on Probability of Impairment: The awareness required is not necessarily a precise, moment-by-moment self-diagnosis of the exact degree of impairment. Rather, it is a recognition of the high probability or likelihood that one's current (or imminently developing) condition, due to substance use, makes normal driving difficult.
• Relevance Beyond Alcohol: While much of the public and legal discussion around impaired driving focuses on alcohol, this case highlights that the same legal principles regarding subjective awareness of impairment apply to driving under the influence of other psychoactive substances, including "dangerous drugs" with unpredictable and severe effects.
• Implications for Habitual Users: The case suggests that for habitual users of impairing substances who have repeatedly experienced the negative effects on their driving, it becomes increasingly difficult to credibly claim a lack of awareness of the risks and their impaired state when they choose to drive after consumption.

Evidentiary Factors for Inferring Subjective Awareness of Impairment

Based on the Osaka High Court case and broader Japanese judicial practice, several categories of circumstantial evidence are commonly used to infer a driver's subjective awareness that they were in a state where normal driving was difficult due to alcohol or drugs:

1. Quantity and Type of Substance Consumed: While not solely determinative, the consumption of a large quantity of alcohol or potent drugs makes it inherently more probable that the driver would be aware of significant impairment.
2. Prior Experiences with the Substance and Impaired Driving: As was central to the Osaka High Court case, a history of experiencing impairment, particularly driving impairment, after consuming the same or similar substances is powerful evidence of current awareness.
3. Observable Signs of Intoxication: Testimony from witnesses (including police officers, friends, or family) about the driver's physical condition and behavior before or during driving—such as slurred speech, unsteady gait, bloodshot eyes, confusion, or erratic actions—can indicate a level of impairment that the driver would likely have been aware of.
4. Driver's Own Statements or Admissions: Any statements made by the driver before, during, or after the incident that acknowledge feeling intoxicated, having difficulty concentrating, or experiencing problems controlling the vehicle can be direct evidence of their subjective awareness.
5. Warnings from Others: If the driver was explicitly warned by others (e.g., "You're too drunk to drive," "You shouldn't drive after taking that") but chose to drive anyway, this can strongly suggest a conscious disregard of their impaired state.
6. Erratic Driving Behavior Prior to the Specific Accident-Causing Maneuver: Evidence of weaving, inconsistent speeds, near misses, or minor collisions before the primary incident that caused death or injury can indicate that the driver was already experiencing and aware of their difficulty in controlling the vehicle, yet continued to drive. Modern evidence sources like dashcams or event data recorders (EDRs) can be crucial here.
7. Circumstances Surrounding the Decision to Drive: Driving for a clearly non-essential or frivolous purpose despite being heavily intoxicated might suggest a reckless disregard that implies an underlying awareness of impairment.
8. Attempts to Evade Detection: If a driver, knowing they are impaired, takes steps to avoid police checkpoints or otherwise attempts to hide their condition, this can indicate an awareness of their unfitness to drive.
9. Time Elapsed Since Consumption and Subjective Feelings: The driver's own account of how they felt (e.g., "feeling the effects strongly," "feeling sleepy/dizzy") can be relevant, though often subject to credibility assessments. The objective time since consumption, in relation to the known pharmacology of the substance, can also help assess the likely state of impairment and awareness.

It is the cumulative weight of such factors, rather than any single piece of evidence, that typically forms the basis for a court's inference regarding the driver's subjective awareness.

Distinction from Article 3 of the Same Act (Driving with a Risk of Impairment)

It is also important to briefly distinguish the offense under Article 2, item 1 (requiring awareness of actual difficulty in normal driving) from a related offense under Article 3, paragraph 1 of the same Act. Article 3 addresses situations where a person drives under the influence of alcohol or drugs such that there is a risk that normal driving may become difficult (正常な運転に支障が生じるおそれがある状態 - seijō na unten ni shishō ga shōjiru osore ga aru jōtai), and then, during that drive, they actually do fall into a state where normal driving is difficult, resulting in death or injury.

The crucial difference lies in the subjective element. For Article 3, the driver only needs to be aware of the risk that their driving ability might become compromised. This is a lower subjective threshold than that required for Article 2, item 1, which demands awareness of an existing or highly probable impending state of difficulty in normal driving. The Osaka High Court case discussed was prosecuted under the higher-threshold provision, equivalent to Article 2, item 1.

Conclusion

The offense of Dangerous Driving Causing Death or Injury due to alcohol or drug impairment, specifically the type predicated on the driver being in a state where "normal driving is difficult," requires the prosecution in Japan to prove a critical subjective element: the driver's awareness of this profound impairment at the time of driving. This is a demanding standard, reflecting the seriousness of the offense and distinguishing it from simple negligence.

As the 2013 Osaka High Court decision involving "dangerous drugs" clearly illustrates, this subjective awareness is not an impenetrable fortress for the defense. Courts can, and do, infer such recognition from a compelling array of circumstantial evidence. A driver's past experiences with impairment caused by the same substances, particularly if those experiences involved driving difficulties, coupled with explicit warnings or even a general understanding of the risks, can lead to a judicial finding that they drove with a conscious appreciation of their severely compromised ability to operate a vehicle safely. This legal approach underscores Japan's commitment to holding accountable those drivers who, with a culpable awareness of their profound impairment, choose to endanger others on the road.