It's a bad idea but we've all done it, driven when we should have been sleeping. We've let our eyelids droop while behind the wheel. In a few heartbeats we realize and snap awake, hopefully while still on the pavement.
Once, when speeding down a desolate, pin straight, empty stretch of Arizona interstate I did exactly that but when I snapped back awake four songs had gone by on the CD.
I choose not to contemplate the potential ramifications of this.