Battalion Chief car

The battalion Chief is used for larger calls as a scene command unit. I'm guessing you're quite new to the game, so you'll need a battalion after you build 6 fire stations and start getting larger calls like roof fire or things of that nature.

Adding to Letsgohope, all missions have a set requirement of units, wheteher it be 1 engine or 10 engines, or more. New calls can be recieved upon building new stations. If you look at the page to buy new vehicles in your fire station, each unit has a "Required at _ stations" tag. This is when a call unlocks that requires the unit. So, calls that require the Bat Chief will come in at 6 stations. Until then it is useless.