First off is the cop car moving or stationary? because if it isn't moving you can bake the lights and then animate them and loop them in matinee and kismet.
I'd put in an omni light with a light function on it that has a panner. Although the animated spotlight would probably give a similar effect.
The big advantage of doing it in matinee is that you can synch it up with other elements. Like an animation on the light. But the light function would be more portable.
I'd use attached spot lights; the lights won't overlap so you're not incurring as much of a cost as by using a light function. Hard attach them to something that rotates. Matinee isn't required, but if it's static you won't need to animate the mesh.
Replies
The big advantage of doing it in matinee is that you can synch it up with other elements. Like an animation on the light. But the light function would be more portable.
Thanks for the help guys!