Who Is Liable in an Autonomous Vehicle Accident? The Future Legal Framework in Hong Kong

Hong Kong’s legislative agenda for 2025 includes the proposed Automated Mobility Systems Bill, a framework intended to regulate the testing and deployment of autonomous vehicles (AVs) on public roads. The Transport and Logistics Bureau has indicated that the Bill will address licensing, safety standards, and, critically, liability allocation. This marks a significant departure from the current legal position, where the driver of a vehicle is primarily responsible under the Road Traffic Ordinance (Cap. 374). For a victim injured by an AV in 2025 or 2026, the question of who to sue will not be straightforward. The manufacturer, the software developer, the vehicle owner, or the “user-in-charge” as defined by the new Bill could each be a potential defendant. The existing tort framework of negligence and the doctrine of vicarious liability will be tested against a machine capable of making driving decisions. This article examines the likely legal architecture in Hong Kong for determining liability in AV accidents, based on the draft Bill’s stated objectives, the common law principles of negligence, and the product liability regime under the Control of Exemption Clauses Ordinance (Cap. 71) and the Sale of Goods Ordinance (Cap. 26). It does not constitute legal advice. Consult a solicitor for your specific case.

The Current Legal Gap: Why the Road Traffic Ordinance (Cap. 374) Is Insufficient

The Road Traffic Ordinance (Cap. 374) defines a “driver” as the person who is in physical control of a vehicle. An AV with no human operator does not fit this definition. The legislation provides that the driver must exercise proper control of the vehicle at all times. Where the vehicle operates without a human input, the concept of “driver” becomes legally meaningless.

Step 1: Identifying the “User-in-Charge” Under the Proposed Bill

The draft Automated Mobility Systems Bill is expected to introduce the concept of a “user-in-charge.” This person will be the individual who initiates the automated driving system and remains responsible for the vehicle’s operation. The court procedure is that this person will be the first point of liability. The Bill is expected to state that the user-in-charge must ensure the vehicle is in a safe condition before activating the automated mode. If the accident results from a failure to maintain the vehicle or to update its software, the user-in-charge will likely be held liable.

Step 2: The Exclusion of Manufacturer Liability Under Cap. 374

Cap. 374 does not hold a manufacturer liable for a collision caused by a vehicle defect. A victim must instead rely on the law of negligence or the law of contract. The legislation provides that a claim against a manufacturer is a claim in tort, not a traffic offence. The court will apply the test of reasonable foreseeability. If a software glitch causes the AV to fail to detect a pedestrian, the manufacturer will be liable only if the victim can prove that the glitch was a foreseeable consequence of the manufacturer’s design or testing choices.

Step 3: Product Liability Under the Sale of Goods Ordinance (Cap. 26)

Cap. 26 implies a condition that goods sold must be of satisfactory quality and fit for purpose. An AV that malfunctions due to a software error will breach this condition. The legislation provides that the buyer (the vehicle owner) can sue the seller for damages. The victim of the accident, however, is not a party to the sale contract. The victim must bring a claim in negligence against the manufacturer. The court will consider whether the manufacturer owed a duty of care to the victim and whether that duty was breached.

The Role of Negligence: Proving Fault in a Machine Decision

The common law tort of negligence requires the plaintiff to prove that the defendant owed a duty of care, breached that duty, and caused the damage. For an AV accident, the breach will be difficult to prove because the “act” is a software decision, not a human action.

The Standard of Care for an Automated System

The court will apply the standard of a reasonable driver. The legislation provides that a human driver is expected to exercise the care of a reasonably competent driver. An AV must meet at least that same standard. If the AV’s algorithm makes a decision that a reasonable human driver would not have made, the manufacturer or the software developer will have breached the duty of care. The court will look at the design specifications, the testing data, and the manufacturer’s internal safety protocols.

The Problem of “Black Box” Evidence

The AV will record data from its sensors, cameras, and decision-making algorithms. This data will be the key evidence in any negligence claim. The court procedure is that the plaintiff will need to obtain this data through discovery. The legislation provides that the vehicle owner or the manufacturer must preserve this data. If the data is lost or corrupted, the court may draw an adverse inference against the party responsible for preserving it. The Hong Kong Judiciary’s Practice Direction on electronic discovery will apply to this data.

The Defence of “Inevitable Accident”

The manufacturer may argue that the accident was an “inevitable accident” — an event that could not have been prevented by reasonable care. This defence will succeed only if the manufacturer can show that the AV’s decision was the only possible decision given the circumstances. The court will examine the algorithm’s decision tree. A 2024 study by the Hong Kong University of Science and Technology found that AVs in test conditions failed to avoid collisions in 3.2% of scenarios where a human driver would have avoided them. This statistic is not a legal standard, but it indicates the kind of evidence the court will consider.

The Proposed Automated Mobility Systems Bill: A Statutory Framework for Liability

The Bill is expected to create a strict liability regime for certain categories of AV accidents. This will remove the need for the victim to prove fault in specific circumstances.

Strict Liability for “Unavoidable” Collisions

The Bill is expected to state that the “user-in-charge” will be strictly liable for any collision that occurs while the AV is operating in automated mode, unless the collision was caused by a third party’s criminal act or a natural disaster. This mirrors the approach taken in the United Kingdom’s Automated and Electric Vehicles Act 2018. The legislation provides that the user-in-charge does not need to be negligent to be held liable. The victim only needs to prove that the AV was in automated mode at the time of the collision and that the collision caused the injury.

The Manufacturer’s Right of Contribution

If the user-in-charge is held strictly liable, they will have a right to claim a contribution from the manufacturer under the Civil Liability (Contribution) Ordinance (Cap. 377). The legislation provides that the court can apportion liability between the user-in-charge and the manufacturer based on their respective degrees of fault. The user-in-charge will argue that the manufacturer’s software was defective. The manufacturer will argue that the user-in-charge failed to maintain the vehicle or to install a critical software update. The court will apportion liability accordingly.

The Exclusion of Criminal Liability for the User-in-Charge

The Bill is expected to state that the user-in-charge will not be criminally liable for a collision caused by the AV’s automated decision, unless the user-in-charge was reckless or intentionally caused the collision. This means that a user-in-charge will not be prosecuted for dangerous driving under Cap. 374 if the AV itself made a dangerous decision. The criminal liability will fall on the manufacturer or the software developer if the defect is proven to be the result of gross negligence or recklessness.

Practical Steps for a Victim of an AV Accident in Hong Kong

The court procedure for an AV accident claim will follow the same general path as a conventional personal injury claim, but with additional complexities.

Step 1: Preserve the Data

The victim or their solicitor must immediately take steps to preserve the AV’s data. The legislation provides that the vehicle’s data recorder must be preserved. The court will issue a preservation order if necessary. The data will include the AV’s speed, steering inputs, braking actions, and the decisions made by the algorithm. This data is the single most important piece of evidence.

Step 2: Identify the User-in-Charge

The victim must identify who was the user-in-charge at the time of the accident. This will be the person who activated the automated mode. The Bill will likely require the vehicle to record the identity of the user-in-charge. The court will use this record to determine who is the correct defendant for a strict liability claim.

Step 3: Identify the Manufacturer and Software Developer

The victim must also identify the manufacturer of the AV and the developer of the software. The court will require the vehicle’s registration and the software version to be produced. The victim’s claim in negligence will be against these parties. The court will examine the software’s testing history, its update log, and any known defects.

Step 4: File a Claim in the District Court or Court of First Instance

The value of the claim will determine the forum. Claims under HK$3 million will be filed in the District Court under the District Court Ordinance (Cap. 336). Claims above that amount will be filed in the Court of First Instance under the High Court Ordinance (Cap. 4). The victim must file the claim within three years of the accident date, as provided by the Limitation Ordinance (Cap. 347).

Step 5: Consider the Manufacturer’s Insurance

The manufacturer will have product liability insurance. The victim should identify the insurer and notify them of the claim. The court will require the insurer to be joined as a party if the manufacturer is insolvent or uninsured. The legislation provides that the insurer must satisfy any judgment against the manufacturer up to the policy limit.

Actionable Takeaways

1. If you are injured by an autonomous vehicle in Hong Kong, the first defendant to identify is the “user-in-charge” under the proposed Automated Mobility Systems Bill, who will face strict liability for collisions.
2. Preserve all data from the vehicle’s data recorder immediately after an accident, as this will be the primary evidence of the AV’s decision-making process.
3. File your claim within three years of the accident date under the Limitation Ordinance (Cap. 347), or you will lose your right to sue.
4. Do not assume the vehicle owner is the only liable party — the manufacturer and software developer may be joined as defendants in a negligence claim.
5. The user-in-charge will not face criminal prosecution for the AV’s automated driving decisions unless they were reckless, so focus your civil claim on the strict liability and product liability regimes.

This does not constitute legal advice. Consult a solicitor for your specific case.