It is illegal to drive a sleigh without bells.

The Law Explained

If you plan on dashing through the snow in a one-horse open sleigh, you better make sure those bells are jingling. An antiquated traffic law requires horse-drawn sleighs to have at least two bells attached to the horse's harness to warn pedestrians of their quiet, snowy approach. Though cars have largely replaced carriages, this law is still technically a requirement for wintery equestrians.