text: The reason is, because the cars really are not fully driverless. if you are in a constrution zone or near an accident the car has you take over. The car isn't full capable of handling driving in a situation like that. The car lets the driver know when they should take over. So the question is " If the car is driverless how come you have to take over in certain situations"? Why can't the car handle it all on its own since the car is smart? For the driverless cars to be very smart they need a bunch of sensors.