What about as a special event as a football game, running/bike race and racetrack events
Football game- similar to the rest 1 ambulance 4-5 cops
Running/bike races- 6-7 cops, 2 ambulances
Racetrack- 2-3 engines, 2-3 ambulances 4-5 cops
Just a random thought as it would add some more diversity to the game.