These car postcard invitations from Hindland are so cool. They are personalised and you print them from your own printer. I love the chevrons and the cute car image!
What about making some racing flags to hang on the walls or getting red, yellow and green balloons to symbolize traffic lights? It can be as low key or as over the top as you want! Here is an example from Catch My Party
These car cakes put the biggest smile on my face. I don't think I could bear to eat them! They are mini cakes with smarties for wheels, being driven by a shortbread teddy! Amazing idea from Paperblog!
As always let me know if you try any of these ideas or if you have any suggestions for future themes!