Mattel actually came out with a Hot Wheels car that is compatible with LEGO bricks and minifigures. It’s aptly named the Fig Rig. The car has four studs on top and a socket on the bottom for LEGO bricks. Minifigure sized handles are on the size and back of the car. There’s even a spot with studs for the minifigure to stand on!
Via Hot Wheels Wikia