air brakes: check
lights: check
horns: check
On a call, the crew relies on the fact that the fire engine and all their gear is in top working condition. How chaotic would it be if they found themselves faced with a critical emergency, and on the way they are forced to sluggishly maneuver through traffic due to a dysfunctional siren? In 2006, the Palo Alto Fire Department responded to 5652 incidents. That breaks down to about 15 calls a day, and for that, they need working equipment. Of those 5652 calls, 3434 of them were medical aid. That comes out to be about 60% of all the calls they receive. So, for the majority of their calls, there are people with injuries, some fatal, and they rely on firefighters to come to rescue with equipment that has been checked and in good condition.