L0: No automation. Human performs all operations. Base cost.
L1: Driver assistance. Human performs most driving operations, system can perform steering OR speed controls. Increased cost.
L2: Partial automation. Human performs most driving operations, system can perform steering AND speed controls. Increased cost.
L3: Conditional automation. System can perform all driving operations, human must be available to intervene in complex situations. Increased cost.
L4: High automation. System can perform all driving operations. Complex situations do not require a human to intervene but intervention is still an option. Decreased cost.
L5: Full automation. System performs all driving operations. Humans are all passengers with no requirement to intervene. Decreased cost.