Apple CarPlay

Hi! This might be a stupid question. But I have the CarPlay in my car, but I was wondering that if Im not in the car, will others see for example my WhatsApp messages or something else? Will it work if I'm not there? I know it works with Bluetooth, but I don't want my messages to show, even the old ones or something in the car if somebody else is driving. So Is the CarPlay "shot down" when I'm not in the car?