Hey Lewis,
I'm having a little trouble understanding the red light thing. It appears that the light has a red lens. A red lens on a white light source is not the same as infrared. I thought white light, full visible spectrum, is always better for unassisted human eyes to "see" at low light levels?
As for as mammals, most nocturnal animals will typically have way better night vision than humans - more rods. If you are driving around at night looking for mammals, your truck will most likely alert them way before any light.
Am I reading your objective for the light mounted on your truck cab correctly.
Gnarls.