They are actually built like that, but they have a built-in projector that makes them appear flat to an outside observer. When they crash the projector usually breaks, which is why they then look bent.
Assuming a ground clearance of 10cm, and a wheelbase of 2.4m (source: my ass) then you can construct an arc under the wheels
This arc says you could drive such a car on an earth with radius as small as 7.25m. Actually, it could be slightly smaller because of where the wheels would contact, but I've lost interest
Optometrists are behind this. When you turn mid fourties they'll politely but sternly ask you to consider spectacles with progressive correction. It will make the world just as curvy as they want you to see it.
If you look very closely, you will be able to see that they actually curve with a radius of 6.371km - might want to get your eyes checked if you can't see that...