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The Takeaway

Accidents involving fully autonomous vehicles present unique and complex liability questions. To ensure a proper defense, it’s critical that insurers and policyholders conduct a thorough investigation to determine the responsible parties—which may include vehicle owners and operators, manufacturers, software developers, and even passengers—and what policy or combination of policies may apply.

Introduction

As Level 4 autonomous transportation becomes a reality in the U.S., China, Germany, and Japan, the world moves closer to achieving fully autonomous, self-driving vehicles. Unlike traditional transportation, where the driver bears full responsibility for the safety of themselves and their passengers, Level 4 autonomous vehicles that are functioning within their defined operational conditions allow everyone inside to sit back and enjoy the ride. In a Level 4 vehicle, everyone’s considered a passenger, free to relax, nap, snack, control the music playlist, or scroll endlessly through social media without ever watching the road.

But if no one has to drive, who’s responsible for injuries that can occur while riding in a self-driving car? Traditionally, fault typically lies with a negligent driver. However, self-driving car accidents introduce complex legal challenges. Liability may be attributed to the vehicle owner, the manufacturer, the software developer, the company that maintains the vehicle systems, or the government entity responsible for road conditions.

Understanding the Levels of Autonomous Vehicles

Understanding the complex legal challenges associated with autonomous vehicles requires recognizing the six levels of driving automation defined by the Society of Automotive Engineers (SAE) and the International Organization for Standardization (ISO).

• Level 0: No Automation – The driver controls everything.
• Level 1: Driver Assistance – The vehicle can assist with one task at a time (e.g., steering or speed), but the driver controls everything else and must keep hands on the wheel.  
• Level 2: Partial Automation – The vehicle can autonomously manage multiple tasks simultaneously (e.g., steering and speed) in limited scenarios. The driver must remain alert and ready to take over.
• Level 3: Conditional Automation – The vehicle handles all driving tasks under specific conditions. The driver must be available to intervene when requested by the system or when specific conditions are not met.
• Level 4: High Automation – The vehicle performs all driving tasks within its operational domain and does not require the driver to intervene.
• Level 5: Full Automation – The vehicle performs all driving tasks without human intervention.

The liability for personal injuries or property damage shifts significantly depending on whether the system requires a driver’s intervention.

Who’s Liable? Levels 4 and 5 Autonomous Vehicle Accidents

When a Level 4 vehicle operates without a human driver (e.g., Waymo and Zoox vehicles), liability may fall on several parties:

• Vehicle Owner. Although a Level 4 or Level 5 autonomous vehicle may shift most of its liability to the manufacturer or software developer in cases arising from product defects, the vehicle’s owner may still be held liable for failure to maintain the vehicle.

• Manufacturer. A defect in an autonomous vehicle’s design or manufacturing or a failure to warn consumers of dangers associated with the autonomous vehicle may result in the manufacturer’s liability.
• Software Developer. Accidents caused by software malfunctions, errors in algorithms, or failures to update systems may result in liability shifting to the software developer.
• Company that Maintains Vehicle’s Systems. If improper maintenance and repairs contribute to an accident, then the company or individual responsible for maintaining the vehicle may be held liable.
• Passengers. Passengers may be held liable if they use the autonomous vehicle in a prohibited manner (e.g., overriding safety systems, using the vehicle in prohibited areas or conditions, and ignoring required updates).
• Government. Government entities could face liability if poor road conditions, inadequate signage or traffic signals, or poor infrastructure contribute to an accident.

The Bicyclist Versus an Autonomous Vehicle

A pending California case highlights the complexities and challenges involved in determining fault in accidents involving fully autonomous vehicles.

A bicyclist is suing Waymo and its passengers, alleging that Waymo’s autonomous vehicle—with no driver—parked in a no-stopping zone and allowed its passengers to exit into the bicycle lane. When a passenger opened one of the vehicle’s doors, the door struck the bicyclist. The complaint alleges intentional battery, intentional infliction of emotional distress, negligence, and strict product liability against Waymo and the vehicle’s passengers.

Assigning liability may require access to technical data, software logs, and expert analysis to understand how the vehicle operated at the time of the incident. Additionally, this case raises the question of whether the passengers themselves bear any responsibility for the alleged harm, further complicating the legal analysis.

Autonomous Vehicles in Missouri

Missouri Law and Autonomous Vehicles. If passed, Missouri HB 1166, introduced in February 2025, would be Missouri’s first major step toward regulating this rapidly evolving area of transportation law. This proposed legislation aims to establish comprehensive legal provisions addressing the deployment, operation, and oversight of autonomous vehicle technology within the state.

HB 1166 defines a “fully autonomous vehicle” as a “motor vehicle equipped with an automated driving system designed to function without a human driver as a level 4 or level 5 system under SAE J3016B.” The bill would allow a person to operate a fully autonomous vehicle on the public roads of Missouri without a human driver once the vehicle meets all requirements. Furthermore, it states that when an automated driving system installed on a motor vehicle is engaged, “the automated driving system is considered the driver or operator, for the purpose of assessing compliance with applicable traffic or motor vehicle laws.” Additionally, proof of financial responsibility will be required for a fully autonomous vehicle.

Missouri Insurance Coverage for Autonomous Vehicles. Although insurance coverage for autonomous vehicles operating in Missouri is still an emerging area, it may ultimately include a combination of long-established policies ranging from auto insurance to product liability to cyber insurance.

Traditionally, Missouri law states that all drivers are subject to Missouri’s proof of financial responsibility law. This regulation requires proof of insurance for liability for any personal injury or destruction of another’s property that arises from the ownership, maintenance, or use of a motor .

For autonomous vehicles, coverage might also need to include product liability insurance (to address potential defects or malfunctions in autonomous driving systems) and cyber insurance (to protect against risks associated with data breaches and hacking).

Mitigating Exposure and Defense

Given the complex integration of hardware, software, and third-party components in autonomous systems, liability may no longer rest solely with the vehicle owner or operator. Identifying the responsible party and corresponding policy is essential to mitigating exposure and ensuring a proper defense.