Chains on the bottom of school buses and ambulances... whats that about?

Question

Why do school buses, ambulances, and other large trucks have chains dangling from the underside of them? I've always wondered this

Answer 1

in case they get on icey roads. They hang the chains to store them. Some emergency vehicles have systems that are underneath and a switch press engages the chains while driving without stopping. Very cool!

Answer 2

They are automatic tire chains to so the driver doesn't have to get out of the bus to chain up. They are most commonly seen in areas which get large amounts of snow or ice.

One of the companies which manufactures and markets these chains is On Spot:

http://www.onspot.com/

Answer 3

you