The Boundary Between Level 4 and Level 5 Automation
AI-generated image · US National Wire
While Waymo's vehicles operate without human drivers, the distinction between SAE automation levels rests on operational scope rather than technical independence.
Waymo's automated driving system is classified as SAE Level 4, a designation that persists even though its vehicles can complete trips without a human behind the wheel. As Engadget first reported, the distinction between Level 4 and Level 5 is not based on how autonomous a vehicle appears during a maneuver, but on the conditions under which it is permitted to operate.
Under the Society of Automotive Engineers (SAE) framework, Level 4 systems can handle all driving tasks without human input, but only within a defined operational design domain (ODD). This ODD encompasses specific geography, road types, and weather conditions. In contrast, the National Highway Traffic Safety Administration (NHTSA) describes Level 5 as operating universally, removing these boundaries entirely.
Waymo continues to expand its Level 4 capabilities, such as introducing a sixth-generation Driver designed for more diverse environments and extreme winter weather. However, Engadget reports that expanding into new cities or weather types does not move a system toward Level 5, as it still operates within defined limits.
Achieving Level 5 is significantly more complex because it removes the boundaries that allow developers to identify and test specific scenarios. Waymo noted in 2026 research on collision-avoidance testing that evaluating Level 4 systems is already complicated by the vast number of potentially hazardous scenarios. The difficulty of managing environmental variables was highlighted in May 2026, when Waymo restricted or suspended some operations after encountering flooded roads in San Antonio and Atlanta. Currently, the NHTSA states that Level 5 technology is not available for consumer purchase.