What is main difference between culvert and Bridge?

Culvert 

1. Components of a culvert are comparatively easy to encompass concrete boxes or cells, pipes, high deck or slab and supporting elements.
2. culvert is typically a tunnel like structure that allows water to pass through a road or railway.
3. culvert is a cover structure consist of two sides, a roof and a floor.
4. A bridge spans between 6 meters to 120 meters.

Bridge

1. Basic components of a bridge are superstructures, substructures and decks.
2. A bridge is a route for transport over a large body of water or physical barrier.
3. There is no floor on the bridge as that in the culvert.
4. A small bridge has a span length of 6 meters or less.