Waymo Self-Driving Levels 4 and 5 Explained: An Overview of SAE Automation Levels

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Advancements in autonomous driving technology have made the sight of driverless cars on public roads increasingly common. Waymo’s self-driving vehicles complete trips autonomously, requiring no driving or system monitoring from passengers. However, the company’s system is classified as Level 4 within the framework of the Society of Automotive Engineers (SAE). What is the highest level, Level 5? The difference lies not in the “degree of autonomy” itself, but in where and under what conditions that autonomy is permitted.

Definition of SAE Automation Levels

SAE J3016 defines autonomous driving technology in six stages from Level 0 to Level 5. The U.S. National Highway Traffic Safety Administration (NHTSA) also adopts this framework, clearly delineating the boundaries between each level.

Level 0 has no automation; driving is entirely the human’s role. There may be temporary safety interventions, but basic controls are operated by the human. Level 1 involves continuous system assistance for either steering or acceleration/braking. Level 2 controls both simultaneously, but ultimate driving responsibility remains with the human.

At Level 3, the vehicle assumes the entire driving task under specific conditions. However, the human must be ready to take over driving if prompted by the system. With Level 4, this handover requirement vanishes. As long as the automated system is operating within its designed conditions, occupants are no longer “backup drivers” but simply “passengers.” Level 5 is capable of autonomous driving under all conditions, everywhere, with no human intervention required.

Why Waymo is Classified as Level 4

Waymo’s published safety research describes its autonomous driving system, the “Waymo Driver,” as an SAE Level 4 automated driving system.

This Level 4 classification explains why an empty driver’s seat does not automatically signify Level 5. Waymo’s vehicles can complete rides without anyone holding the steering wheel, but this capability exists within defined operational limitations.

The most critical concept is the “Operational Design Domain (ODD).” The ODD defines the locations and conditions under which an autonomous driving system is designed to operate. Specifically, this includes geographical scope, types of roads, and compatible weather conditions. The SAE defines the ODD as the set of conditions under which the system is designed to function, with Level 4 systems presupposing autonomous operation completion within these boundaries.

The Core Difference Between Level 4 and 5

The presence or absence of an ODD is the decisive watershed between Level 4 and Level 5. Level 4 is fully capable of autonomous driving within a limited ODD. In contrast, Level 5 has no ODD. It signifies a vehicle that can operate on all roads, in all weather conditions, and anywhere.

Currently, Waymo operates services in specific cities and zones, where the road network and traffic environment have been meticulously mapped and integrated into the system. Outside the ODD, the system either cannot maintain autonomous operation or is not designed to be permitted to drive.

Realizing Level 5 requires the complete elimination of the ODD. This necessitates the ability to drive on all types of roads, in all climates, without prior detailed mapping. This is an extremely difficult technical challenge and has not been achieved at a practical level to date.

Technical Barriers to Achieving Level 5

Realizing Level 5 involves multiple technical hurdles. Current Level 4 systems rely on high-precision maps and specific sensor configurations. Level 5 requires generalized perception and decision-making capabilities that can handle unexpected situations and uncharted environments.

Furthermore, to cope with all weather and road conditions, the versatility of sensor technology and AI must be significantly enhanced. Comprehensively covering situations outside the limited ODD—such as rough terrain, construction zones, and the special behaviors of emergency vehicles—is not easy with current technological standards.

The Future of Driving Automation Level

Classification

Novak Božović from Engadget’s staff@engadget.com points out that the difference between Level 4 and Level 5 is not the “degree of autonomy,” but the “scope in which autonomy is permitted.”

The expansion of robotaxi services demonstrates the practicality of Level 4 autonomous driving and underscores the growing reliability of the technology. However, Level 5 is the ultimate goal of full autonomy, and the road to achieving it is long.

In the near term, Level 4 autonomous driving systems are expected to lead the market, with gradual expansions of the ODD. Achieving Level 5 requires groundbreaking advancements across AI, sensors, and infrastructure, and the timeline remains uncertain.

Editorial Opinion

Short-term Impact Starting with Waymo, Level 4 autonomous driving services are expected to continue expanding their operational cities over the next 3 to 6 months. The expansion of ODDs will proceed incrementally, making robotaxis available in more regions. Conversely, no company has yet published a concrete roadmap for achieving Level 5, and there are no signs of an imminent technological breakthrough. Long-term Perspective Over a 1- to 3-year span, Level 4 autonomous driving could become a vital part of transportation infrastructure. Centered on urban areas, an era will dawn where human-driven vehicles and Level 4 autonomous cars coexist. Realizing Level 5 heavily depends on AI’s generalized environmental perception capabilities and the ability to handle all edge cases, posing a long-term challenge on both technological and regulatory fronts. Question from the Editorial Team To achieve Level 5 autonomous driving, technology to completely eliminate the ODD is insufficient; legal frameworks and social consensus enabling coordination with all traffic participants are also essential. Do the technical definition of Level 5 and the legal/social standards for “all-condition operation” align?

References

• “If Waymo cars are Level 4 automation, what does it take to be a Level 5?”, by staff@engadget.com (Novak Božović) — Engadget, 2026-08-22T21:30:00.000Z (ARR)
• Source URL: https://www.engadget.com/2240138/if-waymo-cars-are-level-4-automation-what-is-level-5/