Vision greater then 40; what does it really mean in game terms?

[Greyfell]

I understand that ground vehicles with vision rated higher then forty are assumed to have some sort of ground surveilance radar or similar equipment. But in game terms, I haven't yet noticed exactly what this means. And as expensive as those vehicles can be, I haven't had a lot of oppurtunity to test it out.

Also, there are a handful of vehicles listed as vision '45' in yellow (instead of the green usually used for GSR). Does this mean an improved thermal sight of some sort?