Fashion or functional...?
 

Never noticed before, but my Fiesta mirrors have these little VGs on them...

http://i102.photobucket.com/albums/m...0655890798.jpg

Maybe they do something, maybe they don't...
But from what I understand, thy look like they are properly placed...?

I'd assume functional, as they look rediculous. Possibly to coerce air towards the void of the mirror surface?

My thoughts exactly....
They are pretty low profile to not be hideous...but at the same time, these mirrors are huge!

I wonder if it occurs to car companies that there are much lower hanging fruit?

Incremental steps...
And all the tiny "touches" adds up to measureable improvements :)

I agree, they're probably functional!

On a related note, I asked about the Juke's turn signals... how they stick up, and was told by a Nissan rep that they are actually designed that way to help air go around the side mirrors to be more aerodynamic! Strange little things the automakers do...

Having bumps on the front fender is a common trick to kick air around the mirrors.

wind noise
 

The original mirrors probably produced wind noise which was deemed unacceptable for the production car.
The VGs can alter the resonant frequency of a structure,moving it up or downscale out of the range of human hearing.

I don't think it has much bearing on mpg.
Acoustic, anechoic wind tunnels allow manufacturers to address these issues of Noise,Vibration,and Harshness (NVH) which is a standard procedure for modern auto design.

Honda added these to the Ridgeline mirrors as well - as Phil says, for wind noise reduction.

http://ecomodder.com/forum/showthrea...rrors-977.html