100% Electric Cars

Recently the car Companies are deciding to make new cars to help better our environment, they want to make 100% cars Electric and make a technology that can shut off the internal combustion engine when the car is not moving, which i have no idea what that means. but i think it means to compeletly turn off the engine, so stopping the car to waste its energy. The Vehicle Engineers say that it will work well even when your in traffic when compelty stopping and should have no problem starting back up. This car can go smoothly on the high way maintaining high speeds. For this car it takes hydrogen and oxygen to form water and even making electricity in the process. this is perfect for a 100% Electric powered car