Seems like there are two scenarios here:
First, if its onboard computer & sensors are operating normally, then it would respond the way it was programmed to respond.
Second, if the accident occurred because of a computer or sensor failure, then there is no way to predict how it would respond.
Either way, it seems like there is a thorny legal question raised that has yet to be addressed: if a driverless car hits a pedestrian and keeps going, who commits the hit and run/ leaving the scene of an injury accident misdemeanor or felony? Can an inanimate, autonomous machine be arrested?