Use Redstone blocks
Use Slime blocks
Use Sticky Pistons
Use Pistons
Use Observers
Use Honey blocks
Use a Boat or Minecart for the seat
Build a flat car frame with Slime blocks or Honey blocks
Place Sticky Pistons facing the direction you want the car to move
Attach Observers to trigger the pistons
Add Redstone blocks to power the piston movement
Connect the moving parts with Slime blocks or Honey blocks
Add a Boat or Minecart on top as the driver seat
Test the machine on a flat surface
Adjust the piston and observer timing if needed
Add blocks for the car body and wheels for appearance