I love this fun Pinterest idea! You can buy these (for $20 USD!) but if you do it yourself it makes for a seriously easy and cheap gift idea.
Here’s a road design idea from Pinterest which you could use as a guide. I made mine a lot simpler, as you can see further below!
I made one of these for each of my and G’s brothers for Christmas. We even test drove the cars on each other’s backs in the shop to make sure the wheels would give a good massage – I hope our nephews are putting them to good use!