text: Even though driverless cars can do some things on their own, the human driver must still remain alert and be ready to take over when necessary. For this reason, it is necessary for the car to be ready to notify the driver when a problem occurs. GM has developed driver's seats that vibrate when the vehicle is in danger of backing into an object, and the Google car announces when the driver should be prepared to take over. These are both ways that can alert a driver when it is time for them to drive, which can help people to be ready to focus while driving.