Police Car



Advantages

The Police Car is fast.
Has the same traction of a roadster.
Large fuel tank.

Disadvantages

Easy to get shot inside due to the many windows.
It can attract the unwanted attention of zombies, or hostile players if the siren is used.


Firetruck



Advantages

It has a huge fuel tank.
Its width makes ramming players, zombies or vehicles easier.

Disadvantages

Despite its large size, the Fire truck is a very ineffective group transport, as it only has two seats, the driver and passenger's seat.
It is very uncommon, and is only found in fire stations.
It is slow, having a top speed of 39 km/h or 24 mph.
The front window is quite big without any cover, making the driver and front seat passenger vulnerable to gunfire.
Its size makes it hard to avoid obstacles while driving.
It can attract the unwanted attention of zombies, or hostile players if the siren is used.

Ambulance



Advantages

High speed.
Very good traction.
Large fuel tank.

Disadvantages

Large Size, hard to dodge obstacles.
No back window.
Low health.
It can attract the unwanted attention of zombies, or hostile players if the siren is used.

Source: http://unturned.wikia.com/wiki/Unturned_Bunker_Wiki

Other Guides of mine:
Unturned Civilian Vehicles: Advantages and Disadvantages.

Link:
http://steamproxy.net/sharedfiles/filedetails/?id=506889284

I also want to say a big thank you for reading this guide,and I hope you found it helpful.Stay tuned for more guides of mine in the near future!