A semi-autonomous car is one that has some level of automatic control, but is not fully under AI control, requiring the driver to have oversight or take over driving in certain circumstances. Comared to a fully autonomous vehicles, the AI for driving a semi-autonomous vehicle may be simpler, for example simple lane following on major roads. However the AI of a semi-autonomous vehicle must also be able to detect the limits of its own competance and the user interface has to be designed so that the driver can rapidly regain situational awareness during handover.