SAR (Search and Rescue) stations would be a great aspect to the game. These stations can have many different vehicles.
vehicles and expansions
Main:
SAR Truck
SAR Chief
Large SAR truck
Tactical SAR truck
Airport Expansion:
SAR Helicopter
SAR plane
Water Expansion:
Large SAR boat
SAR patrol boat
Light SAR boat (needs SAR Truck/Tac truck)