Side note: to a rounding error, all modern cars can be safely driven right away. Wait a few seconds for the sound of the engine to change, indicating that oil is now happily pumping through all the grindy bits, and then you're ready to go. I'm not saying you want to drag race your neighbor 10 seconds after starting the engine for the first time that day, but once you don't hear the tappets being tappety, it's OK to pull out of your driveway and start moving at a sane pace.