B-Spec Driver Arrows?

[Daco]

What do the arrows on the B-Spec drivers mean?

I figured the green is normal, the orange pointing down a bit means they need rest, but whats the blue? more xp? better driving?

 

[Centura]

I think the online manual mention something about this, but if I would take a guess it would be better driving (blue arrow).

 

[Rossticles]

Driver's form

 

[ASH32]

Driver's form

Which from my experience seems to be effected by morale and fitness and there is no way of telling which one caused the drop. Race too many times with the same driver and it'll drop, don't race him at all and it will drop.