Calculate Max. Force on Car Lights at Highway Speeds

[VooDooCC]

Hello all,
What I'm trying to figure out is how I would calculate the max. force on the lights so I can determine which electromechanics to use for a pan/tilt system.
I know the bar will have 4 lights, but I haven't decided on which lights I'm going to use. I am hoping for an equation I could use to calculate the force on different size lights at highway speeds

Thank you in advance,
Justin

 

[HallsofIvy]

What force are you talking about? The effect of wind speed over the car?

 

[VooDooCC]

Sorry, I was in a hurry typing that earlier.
What I'm talking about is the force of wind on the lights. I'm wanting to calculate this, so I know how strong of an actuator I need to use.

I'm going to be making something similar to but for a different truck and don't want to spend the $1700

 

[HallsofIvy]

That would depend on many different variables, mainly the size and orientation of the lights themselves.