The advent of "Connected Cars" (コネクテッドカー - konekutteddo kā), vehicles equipped with advanced information and communication technology (ICT), is rapidly transforming the automotive landscape in Japan and globally. These vehicles, capable of exchanging data with external systems and increasingly incorporating automated driving functionalities, promise enhanced safety, efficiency, and convenience. However, their proliferation also brings a host of novel legal questions, particularly concerning regulatory compliance, liability in the event of accidents, and the nature and use of evidence in resolving disputes. This article explores these critical issues as they pertain to the evolving mobility ecosystem on Japanese roads.

Understanding Connected Cars and Levels of Driving Automation

A Connected Car is essentially a vehicle that functions as an ICT terminal, capable of two-way communication with external networks and devices. This connectivity enables a wide range of services, such as:

• Automatic Emergency Call Systems (eCall): Automatically notifying emergency services in the event of a serious accident.
• Telematics-Based Insurance: Insurance policies where premiums may be adjusted based on actual driving behavior and mileage (走行実績に応じた保険料 - sōkō jisseki ni ōjita hokenryō), monitored via onboard sensors.
• Stolen Vehicle Tracking and Remote Immobilization: Allowing authorities or owners to locate a stolen vehicle and, in some cases, remotely disable its engine.
• Remote Diagnostics and Over-the-Air (OTA) Software Updates: Enabling manufacturers to monitor vehicle health, diagnose issues remotely, and deploy software updates to improve functionality or address vulnerabilities.
• Advanced Navigation and Infotainment: Providing real-time traffic information, route optimization, and access to various online content and services.

Connectivity is also a crucial enabler for higher levels of Autonomous Driving (自動運転 - jidō unten). The Society of Automotive Engineers (SAE) International has defined six levels of driving automation, which are widely referenced in Japan and globally, to clarify the shifting roles between the human driver and the Automated Driving System (ADS):

• Level 0: No Automation: The human driver performs all aspects of the dynamic driving task (DDT).
• Level 1: Driver Assistance: The ADS provides assistance with either steering or acceleration/deceleration (e.g., adaptive cruise control or lane keeping assist). The human driver performs all other aspects of the DDT.
• Level 2: Partial Automation: The ADS provides assistance with both steering and acceleration/deceleration (e.g., adaptive cruise control and lane keeping assist simultaneously) in specific driving modes. The human driver performs all remaining aspects of the DDT and must continuously monitor the driving environment and be ready to take over.
• Level 3: Conditional Automation: The ADS performs all aspects of the DDT within a limited operational design domain (ODD), but the human driver must be receptive to requests from the ADS to intervene and retake control.
• Level 4: High Automation: The ADS performs all aspects of the DDT and any necessary fallback responses within a limited ODD, even if a human driver does not respond appropriately to a request to intervene. Human attention is not required within the ODD.
• Level 5: Full Automation: The ADS performs all aspects of the DDT under all roadway and environmental conditions that could be managed by a human driver. No human driver is needed.

Currently, many vehicles in Japan are equipped with Advanced Safety Vehicle (ASV - 先進安全自動車 - senshin anzen jidōsha) technologies that correspond to Levels 1 and 2, such as collision damage mitigation braking systems, lane keep assist, adaptive cruise control (ACC), drowsiness alert systems, electronic stability control (ESC), and advanced parking assistance systems. Higher levels of automation are under active development and testing.

Navigating the Current Legal and Regulatory Framework in Japan

The introduction of connected and increasingly autonomous vehicles challenges existing legal frameworks that were primarily designed around human drivers.

A. International Conventions and Japanese Road Traffic Law:
Japan is a signatory to the 1949 Geneva Convention on Road Traffic. Key provisions of this convention include:

• Article 8(5), which stipulates that "Every driver shall at all times be able to control his vehicle or to guide his animals."
• Article 10, which requires that "Every driver of a vehicle shall at all times have his vehicle under control so that he can exercise due and proper care and be in a position to stop his vehicle within the limits of his forward vision and to avoid any traffic obstruction."

These articles, emphasizing constant human control, pose interpretive challenges for higher levels of driving automation (SAE Levels 3 and above), where the ADS assumes significant, or even full, responsibility for the DDT. International bodies like the UN Economic Commission for Europe (UNECE) World Forum for Harmonization of Vehicle Regulations (WP.29) and its Working Party on Road Traffic Safety (WP.1) are actively working on interpretations and potential amendments to address automated driving. For instance, WP.1 has acknowledged that experiments with automated driving systems may be permissible under the current convention if a human driver is present and capable of overriding the system, or even if the system is monitored and can be deactivated remotely by a capable human.

Domestically, Japan's Road Traffic Act (道路交通法 - Dōro Kōtsū Hō) similarly reflects the presumption of human control. Article 70 mandates a driver's duty of safe driving, requiring them to "operate the steering wheel, brakes, and other mechanisms of said vehicle reliably, and to drive at such speed and in such manner as not to cause danger to others, according to the conditions of the road, traffic, and said vehicle." This raises questions about how liability and responsibility are assigned when an ADS is primarily in control. To facilitate testing and development, Japan's National Police Agency (警察庁 - Keisatsuchō) issued a circular on June 1, 2017, outlining guidelines under which public road testing of remote-controlled or highly automated driving systems can be conducted, typically requiring a road use permit (道路使用許可 - dōro shiyō kyoka) and adherence to specific safety protocols.

B. Other Relevant Regulations:
Beyond traffic laws, other regulations come into play:

• Data Privacy: The vast amounts of data collected by connected cars (location, driving behavior, user preferences, potentially biometric data) are subject to Japan's Act on the Protection of Personal Information (APPI).
• Cybersecurity: Ensuring the cybersecurity of vehicle systems against hacking and unauthorized access is a growing area of regulatory focus, with specific standards and guidelines emerging.
• Telecommunications Law: Vehicle-to-Everything (V2X) communication systems may fall under the purview of Japan's Telecommunications Business Act.

Japanese government ministries, including the Ministry of Land, Infrastructure, Transport and Tourism (MLIT - 国土交通省) and the Ministry of Economy, Trade and Industry (METI), along with the Cabinet Office's Strategic Innovation Promotion Program (SIP), are actively developing roadmaps and policies to facilitate the safe introduction and deployment of autonomous driving technologies, which includes addressing these legal and regulatory hurdles.

Accident Liability in the Age of Connected and Autonomous Vehicles

The allocation of liability in the event of an accident involving a connected or autonomous vehicle is one of the most complex legal challenges.

A. Japan's Existing Liability Framework:
Traditionally, accident liability in Japan is determined based on:

• Driver Negligence (Tort Law): Under the Civil Code, a driver who negligently causes an accident is liable for the resulting damages.
• Automobile Liability Security Act (自動車損害賠償保障法 - Jidōsha Songai Baishō Hoshō Hō, or 自賠法 - Jibaihō): This Act establishes Japan's compulsory third-party automobile liability insurance system (自賠責保険 - jibaiseki hoken). Article 3 of the Jibaihō imposes a stringent form of liability (often described as being close to strict liability) on the "person who operates an automobile for their own benefit" (運行供用者 - unkō kyōyōsha) for causing death or bodily injury to another through the operation of the automobile. The unkō kyōyōsha can only escape liability if they prove all of the following: (1) that they and the driver exercised due care in connection with the operation of the automobile; (2) that there was intent or negligence on the part of the victim or a third party other than the driver; AND (3) that there was no structural defect or functional disorder in the automobile. This framework primarily addresses personal injury and death, not property damage.

B. Liability Issues Specific to Connected Cars:

• Hacking and Unauthorized Remote Control: A significant concern with connected cars is their vulnerability to hacking, which could allow a malicious third party to remotely commandeer control of the vehicle and cause an accident. In such scenarios:
  • The liability of the vehicle owner/operator under the Jibaihō becomes questionable. Comparisons are often drawn to accidents caused by stolen vehicles. In stolen vehicle cases, the owner's liability may cease if they had exercised due care in securing the vehicle, as their "operational control" and "benefit from operation" are lost.
  • A March 2018 report from an MLIT study group on liability for automated driving suggested that if a vehicle is hacked despite the owner taking appropriate cybersecurity precautions, victims might be compensated through government schemes (similar to those for uninsured accidents), with the government potentially seeking recourse against the manufacturer if a security defect enabled the hack.
  • There is also the potential for product liability claims against the vehicle manufacturer or software provider if the hacking incident was attributable to a security vulnerability that constitutes a "defect." An incident in the U.S. in 2015, where a vulnerability allowing remote control of certain vehicles led to a recall of 1.4 million units, highlighted this risk.

C. Liability in Cases of Autonomous Driving System (ADS) Malfunction or Error:
The introduction of ADSs complicates liability assessment further:

• SAE Level 3 (Conditional Automation): If an accident occurs while the ADS is engaged, liability can be complex. If the system appropriately requested the human driver to retake control and the driver failed to do so in a timely or safe manner, driver negligence may be a primary factor. However, if the ADS malfunctioned, failed to issue a timely takeover request, or made an erroneous decision, then the focus shifts towards the system itself.
• SAE Levels 4 and 5 (High/Full Automation): When the ADS is fully responsible for the DDT and fallback maneuvers within its ODD, establishing driver negligence becomes difficult, if not impossible, as there is no active human "driver" in the traditional sense. Liability considerations then increasingly point towards:
  • Product Liability (製造物責任法 - Seizōbutsu Sekinin Hō): Claims can be brought against the ADS manufacturer or developer if a "defect" in the system (whether in hardware, software, or the AI algorithms) caused the accident. However, proving such a defect in complex, adaptive AI software, and establishing a direct causal link to the accident, can be exceptionally challenging for claimants due to the system's intricacy and often "black box" nature of AI decision-making.
  • Negligence by Manufacturer/Developer (Tort): Beyond product liability, it might be possible to argue that the manufacturer or developer was negligent in the design, development, testing, or deployment of the ADS. However, this typically requires proving a breach of a specific duty of care, which can be difficult.
  • "Structural Defect or Functional Disorder" under Jibaihō: The MLIT study group report considered whether issues external to the vehicle itself, such as errors in high-definition map data used by the ADS or disruptions in V2X communication, could, if the ADS fails to handle them safely, constitute a "structural defect or functional disorder" of the automobile for the purposes of the Jibaihō. The prevailing view appeared to be that ADSs should be designed with sufficient robustness to manage foreseeable issues with external data or connectivity. A failure to ensure such safe operation might be deemed a defect, potentially leading to the unkō kyōyōsha being liable under the Act, but with a subsequent right of recourse against the manufacturer or system provider. Relevant precedents for "structural defect or functional disorder" include Oita District Court, March 2, 1972, and Tokyo High Court, May 30, 1973.

D. Criminal Liability (刑事責任 - keiji sekinin):
If an accident caused by an ADS results in injury or death, the question of criminal liability arises. It would be difficult to assign criminal liability for negligent driving to a human "driver" if the ADS was in full control. Attention might then turn to the potential criminal liability of the vehicle manufacturer, software developers, or corporate executives.
An analogous situation, though not directly involving AI, was a Supreme Court of Japan decision on February 8, 2012 (刑集66巻4号200頁). In that case, managers at a truck manufacturing company were found guilty of professional negligence resulting in death and injury. The case involved a known defect in a truck hub that had caused numerous prior similar accidents, which the company allegedly failed to address adequately and even concealed information about. While the specifics differ, this precedent suggests that in egregious cases of known defects in safety-critical systems and a culpable failure to act, criminal liability for corporate personnel is a possibility in Japan. Applying such principles to complex AI systems will undoubtedly present new legal challenges.

The Pivotal Role of Digital Evidence

Accidents involving connected and autonomous vehicles will necessitate a shift in accident investigation methodologies and the types of evidence considered crucial.

• Beyond Traditional Evidence: While physical evidence (vehicle damage, skid marks, road conditions) and witness testimony will remain important, they will be increasingly supplemented, and in some cases superseded, by digital evidence.
• New Forms of Digital Evidence:
  • Event Data Recorders (EDRs) and Drive Recorders (ドライブレコーダー): These devices are vital. EDRs capture a snapshot of critical vehicle parameters (speed, braking, steering, airbag deployment, system status) immediately before, during, and after a crash. Drive recorders capture video footage and sometimes audio.
  • ADS Logs: The ADS itself will generate detailed operational logs, recording sensor inputs (from cameras, LiDAR, radar), perception data, the AI's decision-making processes, commands issued to vehicle controls, and any system faults or warnings.
  • Software and Algorithm Integrity: In cases of alleged ADS malfunction, examination of the software code, algorithms, and training data may be necessary to identify potential defects, biases, or vulnerabilities.
  • Connectivity and Cybersecurity Logs: Records related to the vehicle's network connections, OTA software updates, and any detected cybersecurity events (e.g., intrusion attempts, malware).
• Challenges in Accessing and Utilizing Digital Evidence:
  • Data Ownership and Access: Complex questions arise about who owns the vast quantities of data generated by connected cars—the vehicle owner, the manufacturer, component suppliers, or service providers. Equally important are questions about who has the legal right to access this data for accident investigation or litigation, and under what conditions.
  • Data Standardization and Interoperability: Lack of standardization in data formats, recording parameters, and access protocols across different vehicle manufacturers and ADS developers can significantly complicate data retrieval and analysis.
  • Preservation and Admissibility: Ensuring that digital evidence is preserved in a forensically sound manner to maintain its integrity and admissibility in legal proceedings is crucial.
  • Technical Expertise: Investigators, legal professionals, and courts will require specialized technical expertise to understand, interpret, and evaluate complex digital evidence from ADSs.

Recognizing these needs, there is a growing international push for standardization of EDRs for automated vehicles. For example, some jurisdictions are considering requirements for EDRs to clearly indicate whether a human or the ADS was in control at the time of an incident. Japan is also actively considering the role and specifications for data recorders to facilitate accurate accident cause analysis for autonomous vehicles.

Conclusion: Charting the Legal Future of Mobility in Japan

Connected cars and the progression towards autonomous driving hold the promise of revolutionizing mobility in Japan, offering potential benefits in safety, efficiency, and accessibility. However, this technological evolution brings with it profound legal and societal questions that are still being actively debated and addressed. Adapting existing legal frameworks—covering road traffic rules, liability regimes, insurance, and evidence gathering—and potentially developing new legislation are ongoing processes that require careful consideration by policymakers, industry stakeholders, legal experts, and the public. The establishment of clear regulations, robust safety standards, well-defined liability rules, and transparent and fair mechanisms for accessing and utilizing digital evidence will be essential for fostering public trust and ensuring the safe, responsible, and beneficial deployment of these advanced mobility solutions on Japan's roads.