They may have the ability to carry that amount of personnel but brush trucks won't carry 3-5 firefighters on a brush truck. It just doesn't make any sense from a financial standpoint nor operational standpoint to over-staff a brush truck. Many brush trucks are cross staffed with another rig's personnel so typically 1-2 people may be utilized for it. Little to none brush trucks are utilized and used to replace a type one engine. They don't have the ability to replace a type 1 engine without compromising level of service. As for the second picture, that would be considered a type 2 fire engine (wildland fire engine). Although they may look similar to a brush truck, they are different in pumping capabilities as well the size of the tank. As for the calls, you can make it to where it is like the pd, ambulances, airport extensions, etc. You don't have to have that unit but if you do, then a certain type of call will require a brush truck or two. That eliminates the issue to where players that have departments that don't utilize brush trucks, can stay realistic and not have to worry about purchasing a brush truck. I forget who it was on the forums but a particular player doesn't utilize any police units so it would be the same case as that players but only for a brush truck.
Again, I created this post as a suggestion from the things that I may like to see implemented into the game. If you are not familiar with some of my ideas, that's okay but don't continue to reply arguing about the same issue over and over again because you don't see these type of rigs from where your located, your not familiar with them, or you don't agree. I appreciate the feedback but it gets tedious having new notifications basically saying the same thing. These units are ALL based off of United States emergency service units throughout the country and this version of Mission Chief is in fact based off of the United States.