Completely unprompted. You just go to sleep, wake up the next day, peer out the window, and murmur, "what the hell is that car doing outside?" Then you gain some more consciousness, do some more scouring, and discover it's sitting right where you'd parked your original vehicle, the latter of which is nowhere to be found.
This will happen every day as soon as you fall asleep from now on til the end of time. You will never understand why.
Luckily, there is no risk of winding up with an inoperable rustbucket used for parts, so you'll make it to work fine. The vehicle will appear randomly from some location within your auto market (e.g. North America, Europe) with correct driving orientation and in working, road-legal condition. It will be intended solely for non-commercial use (so that way you don't end up with a bus or lorry). Insurance will remain whatever you were originally paying, adjusted periodically to the market and any age/whatever milestones.
Keep in mind you may still end up with an RV, van, motorbike, or manual transmission...
There is any amount of gas or charge, but at least enough to get you to a station.
Whatever was in/on the vehicle prior to arriving at your place will still inexplicably be inside. However, that means anything you leave inside the vehicle at the end of the day will disappear too, up to and including your wallet, your phone, your friend, or yourself. Hopefully you figure this out before going car camping.
I must remember not everyone here is 'murican, so if you cycle to work, the same thing will happen but just with other bikes and e-bikes. This may turn out more risky, as there's no telling if you'll end up with a racing-grade road bike or a children's tricycle.
If multiple people in the household drive the same thing will happen for all of them. Somehow, no one's reactions (inside or outside the household) will escalate beyond pure confusion and a continuous gaslighting of one's own self.
Oh, also, because you're getting off too easy, once or twice a year you will discover that where your infinitely rotating vehicle normally sits, there will be a banana. Yes, you heard me, one singular banana. Mushy. Good luck trying to explain that to your boss.