It was the latest twist in a saga that has disrupted typical car industry practices and drawn the attention of safety advocates and regulators, who fear the consequences of Tesla foisting the largely untested software on the public. Full Self-Driving is an expanded iteration of the software that Tesla calls Autopilot, which can navigate highways, summon and park cars, and conduct other maneuvers with an attentive driver behind the wheel. Full Self-Driving brings those capabilities to city streets, allowing the software to navigate Tesla cars through local roads and residential areas. Users must pay attention at all times, and the software — despite its name — is not considered autonomous by industry or regulatory definitions.