In light of the high fuel costs, why do I see fire engines running with no one in them outside of the station in the winter?

The Hudson Fire Department has a no idling policy which requires a fire engine or other emergency vehicle not operating at a scene of an emergency to turn the vehicle off if it will be run more than 10 minutes. The exception to this policy is for the fire engines which carry water and have a large pump to move water. In the winter months, if a fire engine cannot be housed inside then the fire engine is left running and the pump is working to circulate water to prevent freezing. You can imagine what happens when the pump is not circulating in that the pump can freeze up and crack the pump housing resulting in major damage to the fire engine. The fire engines burn diesel fuel which consumes fuel at a slower rate than gasoline.