It took until 2018, but we FINALLY caught up with a modern Stone Age family.
A Dutch engineering company just created a car that you move with your feet. Just like in "The Flintstones".
The big difference is that you don't have to run on the ground to make the car move . . . instead of a gas pedal, it's got a set of bicycle pedals. And to make the car go, you've gotta use 'em.
You don't use your feet to brake though, you use a hand brake on the steering wheel . . . kind of like how the brake on a bike works.