To give an example, we recently had a house fire where three sections of our hose were run over. The hose itself can cost around $700 per section ($2100 possibly ruined after this fire). Even if the hose doesn't appear to be damaged, we still have to send it out to be inspected (more $$$) to ensure it won't rupture on us in the future. If you do run our hose over, it is likely we will be asking for your insurance information to bill you for the damages (maybe for a brand-new hose if it damaged beyond reasonable repair). Another way you can be charged for damages is via a police citation. A ticket, with court costs, can run near $200. Finally, if that is not convincing enough, there is a possibility you could injure, or even kill, our teams fighting the fire if you rupture the hose as that water is what keeps them alive inside of a fire.
Here is an analogy that can put this into perspective: While driving our fire trucks we run into your car. Do you forgive us and not ask us to pay to fix your car? Unless you are the nicest millionaire on earth, the likely answer is going to be "No!" You rely on the car to fulfill some function for you and you weren't the cause of its damage. The same philosophy goes for us. If you run over the hose, you can possibly damage it... this can hurt firefighters... it will take the hose out of service until it can be tested... this leaves a truck short of hose to help someone in the event of a fire... and it would have cost us money we should put into serving you, the community, in a better way.
If you have any questions, please feel free to ask. Below are the links to the Alabama Driver's Handbook and the the state law about not driving over a fire hose. Thanks, in advance, for your assistance, and please be safe out there!
Driver's Handbook (link to .pdf file) (.pdf file page 67, book page 65)
FOLLOWING EMERGENCY VEHICLES
Only vehicles on necessary official business are permitted to follow within 500 feet of emergency vehicles on an emergency run. Don’t drive over an unprotected fire hose unless authorized to do so by a police officer or fire department official.
Alabama State Law (Section 32-5A-59)
Crossing fire hose.
No vehicle shall be driven over any unprotected hose of a fire department when laid down on any street, private road or driveway to be used at any fire or alarm of fire, without the consent of the fire department official or police officer in command.
(Acts 1980, No. 80-434, p. 604, §11-110.)