4.1. Distribution of the Burden of Proof in the Driver's Liability of Autonomous Vehicles
The burden of proof is closely related to the liability for damages. Article 823 of the German Civil Code establishes a general liability clause based on fault. Under this article, automobile drivers may be liable for damages in autonomous driving traffic accidents, provided that the driver is at fault. Also, in accordance with the German Road Traffic Law (Straßenverkehrsgesetz), Paragraph 1 of Article 18 stipulates that a motor vehicle driver who causes death, injury to others, or damage to property while operating a motor vehicle shall be presumed at fault.
To meet the liability conditions of Article 18, Paragraph 1 of the Road Traffic Law, two essential criteria must be satisfied. Firstly, the driver must be the "actual driver" of the motor vehicle. For the first requirement, the driver's scope driver's scope is outlined in paragraph 4 of Article 1a of the Road Traffic Law. Even if the driver has activated the functions of high driving automation (L3) or full driving automation (L4) and relinquished control of the vehicle to the driving system, they are still considered the driver of the vehicle. In the legal context, drivers also encompass individuals who relinquish independent driving control and allow the vehicle to operate automatically. Therefore, the driver cannot evade liability by claiming to be a "non-real driver." Secondly, the driver must exhibit intentional or negligent driving behavior while operating the vehicle, determining whether they have fulfilled their duty of care. The injured party is tasked with the burden of proof for the first and second elements, providing evidence to establish that the driver is indeed the "actual driver" and that the driver either failed to meet the required duty of care or engaged in intentional or negligent driving during the operation of the vehicle.
While differing in specifics, the fault tort liability outlined in Article 823 of the Civil Code and the driver's presumed fault liability delineated in Article 18 of the Road Traffic Law share a common underlying duty of care. In full driving autonomous (L5) instances, the shift or exclusion of the driver's responsibility is attributable to the vehicle being entirely system-controlled. Consequently, the driver assumes the role of a passenger and is exempted from bearing any traffic-related duty of care during the vehicle's operation [
7]. Nonetheless, the obligation for continuous monitoring remains.
That is, in both traditional and autonomous driving contexts, it is the driver's obligation to ensure the vehicle's safety and roadworthiness prior to operation. Should the driver recognize potential safety hazards with the vehicle and not take remedial measures, they might be considered to have neglected their oversight obligations. Nonetheless, with Conditional (L3) or High (L4) driving automation, the driver must fulfill not only the supervisory obligations but also the duty of care concerning the operation and management of the vehicle.
For instance, if the driver exceeds the speed limit or overtakes improperly, resulting in an accident, it constitutes a breach of their duty of care. In Article 1b of the Road Traffic Law, the rights and obligations of drivers in the context of automated driving are clarified. Paragraph 1 of this article stipulates that when a vehicle driver activates the aforementioned automated driving functions, they may no longer need to maintain constant attention to the road traffic environment and vehicle handling. However, the driver must maintain a "ready" state to fulfill the obligations in paragraph 2 of Article 1b.
Specifically, the driver is obligated to promptly resume control of the vehicle if any of the following conditions are met: First, if the system prompts the driver to regain control(Article 1B, Paragraph 2, Item 1); second, even if the system does not prompt, but the driver either recognizes or should recognize, based on clear circumstances, that the conditions necessary for the continued use of highly or fully automated driving systems are no longer present(Article 1B, Paragraph 2, Item 2). In the first cases where a driver fails to promptly respond to a takeover request from an automated driving system, their actions may be deemed responsible for accidents resulting from violations of traffic regulations.
However, this situation leads to the 'operator dilemma': drivers are expected to monitor the vehicle and traffic environment to mitigate risks, yet introducing automatic driving systems aims to relieve drivers of these tasks, resulting in inherent contradictions. Therefore, it is essential to delineate further the specific duty of care that drivers must maintain while utilizing the autonomous driving function and to establish a reasonable takeover time based on the actual circumstances. Research findings in traffic psychology indicate that the driver may require several seconds to complete the takeover of the vehicle. However, legislation has not definitively outlined what constitutes a reasonable and timely takeover duration. Nevertheless, the driver's response under psychological influence must be deemed reasonable. If their behavior deviates significantly from general life experience and appears highly unusual and unexpected, it can be inferred that they have failed to fulfill the relevant duty of care [
8].
In the second scenario, the driver is obligated to take control of the vehicle even without a takeover prompt, particularly in situations deemed obvious. These 'obvious circumstances' typically entail conditions where a rational driver would recognize the necessity to assume control, such as sudden rainstorms, earthquakes, or other emergencies, where continued operation of the automatic driving function could pose a threat. Naturally, it is improbable for legislation to adopt a fully enumerative model; for instance, opting for a more general description, as observed in German legislation, would be an acceptable approach.
It is imperative to clarify that in most cases, drivers are not held liable during conditionally (L3) or highly (L4) automated driving scenarios. The autonomous vehicle operates autonomously, so the driver is not liable for traffic violations in such circumstances. Even if the driver must continue to supervise the vehicle, they are still required to pay necessary attention, but this does not directly attribute responsibility to the driver. The duty of supervision does not mandate drivers to be constantly prepared to detect driving risks, and it is limited to specific circumstances. Even if the driver has recognized or should have recognized the need to take appropriate measures, when an accident occurs suddenly without sufficient reaction time for the driver to assume control of the vehicle, it becomes challenging to avoid the accident, rendering the driver not liable. Suppose the driver fails to promptly assume control of the vehicle or take other necessary measures, resulting in the accident within the interval from when the driver becomes aware or should become aware of a potential hazard until the accident transpires. In that case, they can be held accountable for negligence.
Table 2.
Role of the user after the activation of the driving automation system.
Table 2.
Role of the user after the activation of the driving automation system.
user |
User Roles(Driving automation system activation) |
L0 |
L1 |
L2 |
L3 |
L4 |
L5 |
Users in driving seats |
Traditional Driver |
Driving Mission Support Users |
passenger |
Users not in the driver's seat |
Remote Driver |
passenger |
Users outside the vehicle |
Remote Driver |
dispatcher |
4.2. Mitigation of the Burden of Proof in the Driver's Liability of Autonomous Vehicles
Based on Article 823 of the German Civil Code, the infringed party may request the driver of an autonomous vehicle to assume the liability for damage for compensation arising from tort. The article adopts the fault-based liability fixation mode within tort law. Therefore, the injured party must demonstrate the driver's fault or negligence in fulfilling their duty of care and establish the causal relationship between the tort and resulting damages. The injured party may submit a claim and prove whether the driver activated the vehicle's automatic driving function at the time of the accident, in accordance with the information specified in Article 63a, paragraph 3, of the Road Traffic Law. In conditionally or highly automated driving, the driver is generally absolved of tort liability, with liability only arising in very few exceptional circumstances.
However, the driver still bears the burden of fault presumption as stipulated in the Road Traffic Law. Based on the shift in the legal burden of proof regarding fault, the driver must furnish evidence demonstrating their lack of fault or establish that the accident resulted from a defect or technical issue with the autonomous vehicle. According to Article 63a of the Road Traffic Law, an autonomous vehicle shall be equipped with an electronic driving recorder to fix the evidence to avoid difficulties in adducing evidence. The recorder must precisely document the exact time and location of the transfer of control from the driver to the automated system. If the system autonomously operates the vehicle at the time of the accident, it can, in principle, demonstrate that the driver is not liable. Furthermore, it is imperative to precisely document the timestamp and location when the system issues a takeover reminder or experiences a technical failure and to compare this information with the data recorded during the accident. If the takeover request and the occurrence of the technical breakdown are closely aligned with the time of the accident, it can be inferred that the driver did not have adequate time to respond to the traffic incident.