They are small cars for people to collect for fun. They have facts and information as well as some fun trivia. There are 18 cards to collect from all the forms of transportation. The Friendship boats aren’t part of the collection and those CMs don’t have cards to hand out.
My son got all 18 over several trips by asking all the bus drives, monorail pilots, and boat captains. He had fun collecting them and they’re something nice to take home.