It’s good to see that a few manufacturers are fitting these in their trucks.
But why are they so quiet to start off with and slowly build up in volume ■■?
Why are they not just the same as household ones ?
Are they scared it might wake the neighbours in the truckstop, or a driver asleep on the bottom bunk suddenly jumping up and knocking himself out on the top bunk ?
As the fire service say "every second counts ", surely that few seconds could make a difference.
And why are they not wired into the vehicle electrics ■■?
Bleedin strange that, the one at me girlfriends gaff make a hell of noise when we do a fry up and forget to shut the kitchen door, with the amount of electrics around now they should be wired into the main loom makes more sense. 
They are battery powered so the smokers can take batteries out 
WHAT HAVE I SAID 
And why are they not wired into the vehicle electrics ■■?
It may not be much use if your electrical systems are on fire 
Granted, a battery backup is a possibility in that situation.
But why are they so quiet to start off with and slowly build up in volume ■■?
Maybe in case it goes off while driving? Don’t want to scare the living ■■■■ out of the driver?