Drawing with cars, fun mark making activity for toddlers and preschoolers.
Frozen Car Rescue Science Melting Ice Activity great for learning about different feelings, ice, melting, freezing etc. I would have this outside in a big sensory table.
Miniminds (or a magnet workshop) Make science fun and playful by making a magnet powered car! Make a road and see if you can push/pull your car in the right direction without touching it.