What is the custom of throwing change for a new car?

Answer 1

Car coining

There is a practice in New Jersey and New York of tossing a few coins onto the floor of a newly purchased car as a sign of good luck. This practice originated as a practical one. Because of the area's many toll roads, many drivers would carry change in their cars. The friends and family of the new car owner would throw coins onto the floor of the new car so if they driver ever ran out of his own money, he could always reach down and find some extra money on the floor.