Who is liable for autonomous driving accidents?

What the Law Says

Japanese law imposes strict liability on the owner of a motor vehicle involved in an accident, including those operating in autonomous mode. This means liability applies regardless of fault or negligence.

The Automobile Damage Compensation Security Act (ADCSCA) establishes mandatory insurance and strict liability for vehicle owners. Under this law, the owner must compensate victims for death, injury, or property damage arising from the operation of a motor vehicle — even if the vehicle was in autonomous mode and the owner was not actively driving.

The law defines 'operation' broadly to include situations where the vehicle is functioning under automated control systems. The owner cannot avoid liability simply because the vehicle was self-driving at the time of the accident.

Exceptions are extremely narrow: the owner may be relieved of liability only if they can prove the accident resulted from force majeure (e.g., sudden natural disaster) or was caused solely by the victim’s intentional act or gross negligence — a high burden that rarely applies.

Statutory Text

The possessor of an automobile shall be liable to compensate any person who has suffered loss or damage as a result of the operation of the automobile.

— Automobile Damage Compensation Security Act, s. 3 — Liability for Damage Caused by Automobiles

Statutory Text

The possessor shall not be liable if he proves that the damage was caused by force majeure or by the intentional act or gross negligence of the victim.

— Automobile Damage Compensation Security Act, s. 3 — Liability for Damage Caused by Automobiles

What to Do

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